\input texinfo @c -*-texinfo-*- @c %**start of header @setfilename wget.info @include version.texi @set UPDATED Apr 2005 @settitle GNU Wget @value{VERSION} Manual @c Disable the monstrous rectangles beside overfull hbox-es. @finalout @c Use `odd' to print double-sided. @setchapternewpage on @c %**end of header @iftex @c Remove this if you don't use A4 paper. @afourpaper @end iftex @c Title for man page. The weird way texi2pod.pl is written requires @c the preceding @set. @set Wget Wget @c man title Wget The non-interactive network downloader. @dircategory Network Applications @direntry * Wget: (wget). The non-interactive network downloader. @end direntry @ifnottex This file documents the the GNU Wget utility for downloading network data. @c man begin COPYRIGHT Copyright @copyright{} 1996--2005 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. @ignore Permission is granted to process this file through TeX and print the results, provided the printed document carries a copying permission notice identical to this one except for the removal of this paragraph (this paragraph not being relevant to the printed manual). @end ignore Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being ``GNU General Public License'' and ``GNU Free Documentation License'', with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. @c man end @end ifnottex @titlepage @title GNU Wget @value{VERSION} @subtitle The non-interactive download utility @subtitle Updated for Wget @value{VERSION}, @value{UPDATED} @author by Hrvoje Nik@v{s}i@'{c} and others @ignore @c man begin AUTHOR Originally written by Hrvoje Niksic . @c man end @c man begin SEEALSO GNU Info entry for @file{wget}. @c man end @end ignore @page @vskip 0pt plus 1filll Copyright @copyright{} 1996--2005, Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being ``GNU General Public License'' and ``GNU Free Documentation License'', with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. @end titlepage @ifnottex @node Top @top Wget @value{VERSION} This manual documents version @value{VERSION} of GNU Wget, the freely available utility for network downloads. Copyright @copyright{} 1996--2005 Free Software Foundation, Inc. @menu * Overview:: Features of Wget. * Invoking:: Wget command-line arguments. * Recursive Download:: Downloading interlinked pages. * Following Links:: The available methods of chasing links. * Time-Stamping:: Mirroring according to time-stamps. * Startup File:: Wget's initialization file. * Examples:: Examples of usage. * Various:: The stuff that doesn't fit anywhere else. * Appendices:: Some useful references. * Copying:: You may give out copies of Wget and of this manual. * Concept Index:: Topics covered by this manual. @end menu @end ifnottex @node Overview @chapter Overview @cindex overview @cindex features @c man begin DESCRIPTION GNU Wget is a free utility for non-interactive download of files from the Web. It supports @sc{http}, @sc{https}, and @sc{ftp} protocols, as well as retrieval through @sc{http} proxies. @c man end This chapter is a partial overview of Wget's features. @itemize @bullet @item @c man begin DESCRIPTION Wget is non-interactive, meaning that it can work in the background, while the user is not logged on. This allows you to start a retrieval and disconnect from the system, letting Wget finish the work. By contrast, most of the Web browsers require constant user's presence, which can be a great hindrance when transferring a lot of data. @c man end @item @ignore @c man begin DESCRIPTION @c man end @end ignore @c man begin DESCRIPTION Wget can follow links in @sc{html} and @sc{xhtml} pages and create local versions of remote web sites, fully recreating the directory structure of the original site. This is sometimes referred to as ``recursive downloading.'' While doing that, Wget respects the Robot Exclusion Standard (@file{/robots.txt}). Wget can be instructed to convert the links in downloaded @sc{html} files to the local files for offline viewing. @c man end @item File name wildcard matching and recursive mirroring of directories are available when retrieving via @sc{ftp}. Wget can read the time-stamp information given by both @sc{http} and @sc{ftp} servers, and store it locally. Thus Wget can see if the remote file has changed since last retrieval, and automatically retrieve the new version if it has. This makes Wget suitable for mirroring of @sc{ftp} sites, as well as home pages. @item @ignore @c man begin DESCRIPTION @c man end @end ignore @c man begin DESCRIPTION Wget has been designed for robustness over slow or unstable network connections; if a download fails due to a network problem, it will keep retrying until the whole file has been retrieved. If the server supports regetting, it will instruct the server to continue the download from where it left off. @c man end @item Wget supports proxy servers, which can lighten the network load, speed up retrieval and provide access behind firewalls. However, if you are behind a firewall that requires that you use a socks style gateway, you can get the socks library and build Wget with support for socks. Wget uses the passive @sc{ftp} downloading by default, active @sc{ftp} being an option. @item Wget supports IP version 6, the next generation of IP. IPv6 is autodetected at compile-time, and can be disabled at either build or run time. Binaries built with IPv6 support work well in both IPv4-only and dual family environments. @item Built-in features offer mechanisms to tune which links you wish to follow (@pxref{Following Links}). @item The progress of individual downloads is traced using a progress gauge. Interactive downloads are tracked using a ``thermometer''-style gauge, whereas non-interactive ones are traced with dots, each dot representing a fixed amount of data received (1KB by default). Either gauge can be customized to your preferences. @item Most of the features are fully configurable, either through command line options, or via the initialization file @file{.wgetrc} (@pxref{Startup File}). Wget allows you to define @dfn{global} startup files (@file{/usr/local/etc/wgetrc} by default) for site settings. @ignore @c man begin FILES @table @samp @item /usr/local/etc/wgetrc Default location of the @dfn{global} startup file. @item .wgetrc User startup file. @end table @c man end @end ignore @item Finally, GNU Wget is free software. This means that everyone may use it, redistribute it and/or modify it under the terms of the GNU General Public License, as published by the Free Software Foundation (@pxref{Copying}). @end itemize @node Invoking @chapter Invoking @cindex invoking @cindex command line @cindex arguments @cindex nohup By default, Wget is very simple to invoke. The basic syntax is: @example @c man begin SYNOPSIS wget [@var{option}]@dots{} [@var{URL}]@dots{} @c man end @end example Wget will simply download all the @sc{url}s specified on the command line. @var{URL} is a @dfn{Uniform Resource Locator}, as defined below. However, you may wish to change some of the default parameters of Wget. You can do it two ways: permanently, adding the appropriate command to @file{.wgetrc} (@pxref{Startup File}), or specifying it on the command line. @menu * URL Format:: * Option Syntax:: * Basic Startup Options:: * Logging and Input File Options:: * Download Options:: * Directory Options:: * HTTP Options:: * HTTPS (SSL/TLS) Options:: * FTP Options:: * Recursive Retrieval Options:: * Recursive Accept/Reject Options:: @end menu @node URL Format @section URL Format @cindex URL @cindex URL syntax @dfn{URL} is an acronym for Uniform Resource Locator. A uniform resource locator is a compact string representation for a resource available via the Internet. Wget recognizes the @sc{url} syntax as per @sc{rfc1738}. This is the most widely used form (square brackets denote optional parts): @example http://host[:port]/directory/file ftp://host[:port]/directory/file @end example You can also encode your username and password within a @sc{url}: @example ftp://user:password@@host/path http://user:password@@host/path @end example Either @var{user} or @var{password}, or both, may be left out. If you leave out either the @sc{http} username or password, no authentication will be sent. If you leave out the @sc{ftp} username, @samp{anonymous} will be used. If you leave out the @sc{ftp} password, your email address will be supplied as a default password.@footnote{If you have a @file{.netrc} file in your home directory, password will also be searched for there.} @strong{Important Note}: if you specify a password-containing @sc{url} on the command line, the username and password will be plainly visible to all users on the system, by way of @code{ps}. On multi-user systems, this is a big security risk. To work around it, use @code{wget -i -} and feed the @sc{url}s to Wget's standard input, each on a separate line, terminated by @kbd{C-d}. You can encode unsafe characters in a @sc{url} as @samp{%xy}, @code{xy} being the hexadecimal representation of the character's @sc{ascii} value. Some common unsafe characters include @samp{%} (quoted as @samp{%25}), @samp{:} (quoted as @samp{%3A}), and @samp{@@} (quoted as @samp{%40}). Refer to @sc{rfc1738} for a comprehensive list of unsafe characters. Wget also supports the @code{type} feature for @sc{ftp} @sc{url}s. By default, @sc{ftp} documents are retrieved in the binary mode (type @samp{i}), which means that they are downloaded unchanged. Another useful mode is the @samp{a} (@dfn{ASCII}) mode, which converts the line delimiters between the different operating systems, and is thus useful for text files. Here is an example: @example ftp://host/directory/file;type=a @end example Two alternative variants of @sc{url} specification are also supported, because of historical (hysterical?) reasons and their widespreaded use. @sc{ftp}-only syntax (supported by @code{NcFTP}): @example host:/dir/file @end example @sc{http}-only syntax (introduced by @code{Netscape}): @example host[:port]/dir/file @end example These two alternative forms are deprecated, and may cease being supported in the future. If you do not understand the difference between these notations, or do not know which one to use, just use the plain ordinary format you use with your favorite browser, like @code{Lynx} or @code{Netscape}. @c man begin OPTIONS @node Option Syntax @section Option Syntax @cindex option syntax @cindex syntax of options Since Wget uses GNU getopt to process command-line arguments, every option has a long form along with the short one. Long options are more convenient to remember, but take time to type. You may freely mix different option styles, or specify options after the command-line arguments. Thus you may write: @example wget -r --tries=10 http://fly.srk.fer.hr/ -o log @end example The space between the option accepting an argument and the argument may be omitted. Instead @samp{-o log} you can write @samp{-olog}. You may put several options that do not require arguments together, like: @example wget -drc @var{URL} @end example This is a complete equivalent of: @example wget -d -r -c @var{URL} @end example Since the options can be specified after the arguments, you may terminate them with @samp{--}. So the following will try to download @sc{url} @samp{-x}, reporting failure to @file{log}: @example wget -o log -- -x @end example The options that accept comma-separated lists all respect the convention that specifying an empty list clears its value. This can be useful to clear the @file{.wgetrc} settings. For instance, if your @file{.wgetrc} sets @code{exclude_directories} to @file{/cgi-bin}, the following example will first reset it, and then set it to exclude @file{/~nobody} and @file{/~somebody}. You can also clear the lists in @file{.wgetrc} (@pxref{Wgetrc Syntax}). @example wget -X '' -X /~nobody,/~somebody @end example Most options that do not accept arguments are @dfn{boolean} options, so named because their state can be captured with a yes-or-no (``boolean'') variable. For example, @samp{--follow-ftp} tells Wget to follow FTP links from HTML files and, on the other hand, @samp{--no-glob} tells it not to perform file globbing on FTP URLs. A boolean option is either @dfn{affirmative} or @dfn{negative} (beginning with @samp{--no}). All such options share several properties. Unless stated otherwise, it is assumed that the default behavior is the opposite of what the option accomplishes. For example, the documented existence of @samp{--follow-ftp} assumes that the default is to @emph{not} follow FTP links from HTML pages. Affirmative options can be negated by prepending the @samp{--no-} to the option name; negative options can be negated by omitting the @samp{--no-} prefix. This might seem superfluous---if the default for an affirmative option is to not do something, then why provide a way to explicitly turn it off? But the startup file may in fact change the default. For instance, using @code{follow_ftp = off} in @file{.wgetrc} makes Wget @emph{not} follow FTP links by default, and using @samp{--no-follow-ftp} is the only way to restore the factory default from the command line. @node Basic Startup Options @section Basic Startup Options @table @samp @item -V @itemx --version Display the version of Wget. @item -h @itemx --help Print a help message describing all of Wget's command-line options. @item -b @itemx --background Go to background immediately after startup. If no output file is specified via the @samp{-o}, output is redirected to @file{wget-log}. @cindex execute wgetrc command @item -e @var{command} @itemx --execute @var{command} Execute @var{command} as if it were a part of @file{.wgetrc} (@pxref{Startup File}). A command thus invoked will be executed @emph{after} the commands in @file{.wgetrc}, thus taking precedence over them. If you need to specify more than one wgetrc command, use multiple instances of @samp{-e}. @end table @node Logging and Input File Options @section Logging and Input File Options @table @samp @cindex output file @cindex log file @item -o @var{logfile} @itemx --output-file=@var{logfile} Log all messages to @var{logfile}. The messages are normally reported to standard error. @cindex append to log @item -a @var{logfile} @itemx --append-output=@var{logfile} Append to @var{logfile}. This is the same as @samp{-o}, only it appends to @var{logfile} instead of overwriting the old log file. If @var{logfile} does not exist, a new file is created. @cindex debug @item -d @itemx --debug Turn on debug output, meaning various information important to the developers of Wget if it does not work properly. Your system administrator may have chosen to compile Wget without debug support, in which case @samp{-d} will not work. Please note that compiling with debug support is always safe---Wget compiled with the debug support will @emph{not} print any debug info unless requested with @samp{-d}. @xref{Reporting Bugs}, for more information on how to use @samp{-d} for sending bug reports. @cindex quiet @item -q @itemx --quiet Turn off Wget's output. @cindex verbose @item -v @itemx --verbose Turn on verbose output, with all the available data. The default output is verbose. @item -nv @itemx --no-verbose Turn off verbose without being completely quiet (use @samp{-q} for that), which means that error messages and basic information still get printed. @cindex input-file @item -i @var{file} @itemx --input-file=@var{file} Read @sc{url}s from @var{file}. If @samp{-} is specified as @var{file}, @sc{url}s are read from the standard input. (Use @samp{./-} to read from a file literally named @samp{-}.) If this function is used, no @sc{url}s need be present on the command line. If there are @sc{url}s both on the command line and in an input file, those on the command lines will be the first ones to be retrieved. The @var{file} need not be an @sc{html} document (but no harm if it is)---it is enough if the @sc{url}s are just listed sequentially. However, if you specify @samp{--force-html}, the document will be regarded as @samp{html}. In that case you may have problems with relative links, which you can solve either by adding @code{} to the documents or by specifying @samp{--base=@var{url}} on the command line. @cindex force html @item -F @itemx --force-html When input is read from a file, force it to be treated as an @sc{html} file. This enables you to retrieve relative links from existing @sc{html} files on your local disk, by adding @code{} to @sc{html}, or using the @samp{--base} command-line option. @cindex base for relative links in input file @item -B @var{URL} @itemx --base=@var{URL} Prepends @var{URL} to relative links read from the file specified with the @samp{-i} option. @end table @node Download Options @section Download Options @table @samp @cindex bind address @cindex client IP address @cindex IP address, client @item --bind-address=@var{ADDRESS} When making client TCP/IP connections, bind to @var{ADDRESS} on the local machine. @var{ADDRESS} may be specified as a hostname or IP address. This option can be useful if your machine is bound to multiple IPs. @cindex retries @cindex tries @cindex number of retries @item -t @var{number} @itemx --tries=@var{number} Set number of retries to @var{number}. Specify 0 or @samp{inf} for infinite retrying. The default is to retry 20 times, with the exception of fatal errors like ``connection refused'' or ``not found'' (404), which are not retried. @item -O @var{file} @itemx --output-document=@var{file} The documents will not be written to the appropriate files, but all will be concatenated together and written to @var{file}. If @samp{-} is used as @var{file}, documents will be printed to standard output, disabling link conversion. (Use @samp{./-} to print to a file literally named @samp{-}.) Note that a combination with @samp{-k} is only well-defined for downloading a single document. @cindex clobbering, file @cindex downloading multiple times @cindex no-clobber @item -nc @itemx --no-clobber If a file is downloaded more than once in the same directory, Wget's behavior depends on a few options, including @samp{-nc}. In certain cases, the local file will be @dfn{clobbered}, or overwritten, upon repeated download. In other cases it will be preserved. When running Wget without @samp{-N}, @samp{-nc}, or @samp{-r}, downloading the same file in the same directory will result in the original copy of @var{file} being preserved and the second copy being named @samp{@var{file}.1}. If that file is downloaded yet again, the third copy will be named @samp{@var{file}.2}, and so on. When @samp{-nc} is specified, this behavior is suppressed, and Wget will refuse to download newer copies of @samp{@var{file}}. Therefore, ``@code{no-clobber}'' is actually a misnomer in this mode---it's not clobbering that's prevented (as the numeric suffixes were already preventing clobbering), but rather the multiple version saving that's prevented. When running Wget with @samp{-r}, but without @samp{-N} or @samp{-nc}, re-downloading a file will result in the new copy simply overwriting the old. Adding @samp{-nc} will prevent this behavior, instead causing the original version to be preserved and any newer copies on the server to be ignored. When running Wget with @samp{-N}, with or without @samp{-r}, the decision as to whether or not to download a newer copy of a file depends on the local and remote timestamp and size of the file (@pxref{Time-Stamping}). @samp{-nc} may not be specified at the same time as @samp{-N}. Note that when @samp{-nc} is specified, files with the suffixes @samp{.html} or @samp{.htm} will be loaded from the local disk and parsed as if they had been retrieved from the Web. @cindex continue retrieval @cindex incomplete downloads @cindex resume download @item -c @itemx --continue Continue getting a partially-downloaded file. This is useful when you want to finish up a download started by a previous instance of Wget, or by another program. For instance: @example wget -c ftp://sunsite.doc.ic.ac.uk/ls-lR.Z @end example If there is a file named @file{ls-lR.Z} in the current directory, Wget will assume that it is the first portion of the remote file, and will ask the server to continue the retrieval from an offset equal to the length of the local file. Note that you don't need to specify this option if you just want the current invocation of Wget to retry downloading a file should the connection be lost midway through. This is the default behavior. @samp{-c} only affects resumption of downloads started @emph{prior} to this invocation of Wget, and whose local files are still sitting around. Without @samp{-c}, the previous example would just download the remote file to @file{ls-lR.Z.1}, leaving the truncated @file{ls-lR.Z} file alone. Beginning with Wget 1.7, if you use @samp{-c} on a non-empty file, and it turns out that the server does not support continued downloading, Wget will refuse to start the download from scratch, which would effectively ruin existing contents. If you really want the download to start from scratch, remove the file. Also beginning with Wget 1.7, if you use @samp{-c} on a file which is of equal size as the one on the server, Wget will refuse to download the file and print an explanatory message. The same happens when the file is smaller on the server than locally (presumably because it was changed on the server since your last download attempt)---because ``continuing'' is not meaningful, no download occurs. On the other side of the coin, while using @samp{-c}, any file that's bigger on the server than locally will be considered an incomplete download and only @code{(length(remote) - length(local))} bytes will be downloaded and tacked onto the end of the local file. This behavior can be desirable in certain cases---for instance, you can use @samp{wget -c} to download just the new portion that's been appended to a data collection or log file. However, if the file is bigger on the server because it's been @emph{changed}, as opposed to just @emph{appended} to, you'll end up with a garbled file. Wget has no way of verifying that the local file is really a valid prefix of the remote file. You need to be especially careful of this when using @samp{-c} in conjunction with @samp{-r}, since every file will be considered as an "incomplete download" candidate. Another instance where you'll get a garbled file if you try to use @samp{-c} is if you have a lame @sc{http} proxy that inserts a ``transfer interrupted'' string into the local file. In the future a ``rollback'' option may be added to deal with this case. Note that @samp{-c} only works with @sc{ftp} servers and with @sc{http} servers that support the @code{Range} header. @cindex progress indicator @cindex dot style @item --progress=@var{type} Select the type of the progress indicator you wish to use. Legal indicators are ``dot'' and ``bar''. The ``bar'' indicator is used by default. It draws an @sc{ascii} progress bar graphics (a.k.a ``thermometer'' display) indicating the status of retrieval. If the output is not a TTY, the ``dot'' bar will be used by default. Use @samp{--progress=dot} to switch to the ``dot'' display. It traces the retrieval by printing dots on the screen, each dot representing a fixed amount of downloaded data. When using the dotted retrieval, you may also set the @dfn{style} by specifying the type as @samp{dot:@var{style}}. Different styles assign different meaning to one dot. With the @code{default} style each dot represents 1K, there are ten dots in a cluster and 50 dots in a line. The @code{binary} style has a more ``computer''-like orientation---8K dots, 16-dots clusters and 48 dots per line (which makes for 384K lines). The @code{mega} style is suitable for downloading very large files---each dot represents 64K retrieved, there are eight dots in a cluster, and 48 dots on each line (so each line contains 3M). Note that you can set the default style using the @code{progress} command in @file{.wgetrc}. That setting may be overridden from the command line. The exception is that, when the output is not a TTY, the ``dot'' progress will be favored over ``bar''. To force the bar output, use @samp{--progress=bar:force}. @item -N @itemx --timestamping Turn on time-stamping. @xref{Time-Stamping}, for details. @cindex server response, print @item -S @itemx --server-response Print the headers sent by @sc{http} servers and responses sent by @sc{ftp} servers. @cindex Wget as spider @cindex spider @item --spider When invoked with this option, Wget will behave as a Web @dfn{spider}, which means that it will not download the pages, just check that they are there. For example, you can use Wget to check your bookmarks: @example wget --spider --force-html -i bookmarks.html @end example This feature needs much more work for Wget to get close to the functionality of real web spiders. @cindex timeout @item -T seconds @itemx --timeout=@var{seconds} Set the network timeout to @var{seconds} seconds. This is equivalent to specifying @samp{--dns-timeout}, @samp{--connect-timeout}, and @samp{--read-timeout}, all at the same time. When interacting with the network, Wget can check for timeout and abort the operation if it takes too long. This prevents anomalies like hanging reads and infinite connects. The only timeout enabled by default is a 900-second read timeout. Setting a timeout to 0 disables it altogether. Unless you know what you are doing, it is best not to change the default timeout settings. All timeout-related options accept decimal values, as well as subsecond values. For example, @samp{0.1} seconds is a legal (though unwise) choice of timeout. Subsecond timeouts are useful for checking server response times or for testing network latency. @cindex DNS timeout @cindex timeout, DNS @item --dns-timeout=@var{seconds} Set the DNS lookup timeout to @var{seconds} seconds. DNS lookups that don't complete within the specified time will fail. By default, there is no timeout on DNS lookups, other than that implemented by system libraries. @cindex connect timeout @cindex timeout, connect @item --connect-timeout=@var{seconds} Set the connect timeout to @var{seconds} seconds. TCP connections that take longer to establish will be aborted. By default, there is no connect timeout, other than that implemented by system libraries. @cindex read timeout @cindex timeout, read @item --read-timeout=@var{seconds} Set the read (and write) timeout to @var{seconds} seconds. The ``time'' of this timeout refers @dfn{idle time}: if, at any point in the download, no data is received for more than the specified number of seconds, reading fails and the download is restarted. This option does not directly affect the duration of the entire download. Of course, the remote server may choose to terminate the connection sooner than this option requires. The default read timeout is 900 seconds. @cindex bandwidth, limit @cindex rate, limit @cindex limit bandwidth @item --limit-rate=@var{amount} Limit the download speed to @var{amount} bytes per second. Amount may be expressed in bytes, kilobytes with the @samp{k} suffix, or megabytes with the @samp{m} suffix. For example, @samp{--limit-rate=20k} will limit the retrieval rate to 20KB/s. This is useful when, for whatever reason, you don't want Wget to consume the entire available bandwidth. This option allows the use of decimal numbers, usually in conjunction with power suffixes; for example, @samp{--limit-rate=2.5k} is a legal value. Note that Wget implements the limiting by sleeping the appropriate amount of time after a network read that took less time than specified by the rate. Eventually this strategy causes the TCP transfer to slow down to approximately the specified rate. However, it may take some time for this balance to be achieved, so don't be surprised if limiting the rate doesn't work well with very small files. @cindex pause @cindex wait @item -w @var{seconds} @itemx --wait=@var{seconds} Wait the specified number of seconds between the retrievals. Use of this option is recommended, as it lightens the server load by making the requests less frequent. Instead of in seconds, the time can be specified in minutes using the @code{m} suffix, in hours using @code{h} suffix, or in days using @code{d} suffix. Specifying a large value for this option is useful if the network or the destination host is down, so that Wget can wait long enough to reasonably expect the network error to be fixed before the retry. @cindex retries, waiting between @cindex waiting between retries @item --waitretry=@var{seconds} If you don't want Wget to wait between @emph{every} retrieval, but only between retries of failed downloads, you can use this option. Wget will use @dfn{linear backoff}, waiting 1 second after the first failure on a given file, then waiting 2 seconds after the second failure on that file, up to the maximum number of @var{seconds} you specify. Therefore, a value of 10 will actually make Wget wait up to (1 + 2 + ... + 10) = 55 seconds per file. Note that this option is turned on by default in the global @file{wgetrc} file. @cindex wait, random @cindex random wait @item --random-wait Some web sites may perform log analysis to identify retrieval programs such as Wget by looking for statistically significant similarities in the time between requests. This option causes the time between requests to vary between 0 and 2 * @var{wait} seconds, where @var{wait} was specified using the @samp{--wait} option, in order to mask Wget's presence from such analysis. A recent article in a publication devoted to development on a popular consumer platform provided code to perform this analysis on the fly. Its author suggested blocking at the class C address level to ensure automated retrieval programs were blocked despite changing DHCP-supplied addresses. The @samp{--random-wait} option was inspired by this ill-advised recommendation to block many unrelated users from a web site due to the actions of one. @cindex proxy @itemx --no-proxy Don't use proxies, even if the appropriate @code{*_proxy} environment variable is defined. For more information about the use of proxies with Wget, @xref{Proxies}. @cindex quota @item -Q @var{quota} @itemx --quota=@var{quota} Specify download quota for automatic retrievals. The value can be specified in bytes (default), kilobytes (with @samp{k} suffix), or megabytes (with @samp{m} suffix). Note that quota will never affect downloading a single file. So if you specify @samp{wget -Q10k ftp://wuarchive.wustl.edu/ls-lR.gz}, all of the @file{ls-lR.gz} will be downloaded. The same goes even when several @sc{url}s are specified on the command-line. However, quota is respected when retrieving either recursively, or from an input file. Thus you may safely type @samp{wget -Q2m -i sites}---download will be aborted when the quota is exceeded. Setting quota to 0 or to @samp{inf} unlimits the download quota. @cindex DNS cache @cindex caching of DNS lookups @item --no-dns-cache Turn off caching of DNS lookups. Normally, Wget remembers the IP addresses it looked up from DNS so it doesn't have to repeatedly contact the DNS server for the same (typically small) set of hosts it retrieves from. This cache exists in memory only; a new Wget run will contact DNS again. However, it has been reported that in some situations it is not desirable to cache host names, even for the duration of a short-running application like Wget. With this option Wget issues a new DNS lookup (more precisely, a new call to @code{gethostbyname} or @code{getaddrinfo}) each time it makes a new connection. Please note that this option will @emph{not} affect caching that might be performed by the resolving library or by an external caching layer, such as NSCD. If you don't understand exactly what this option does, you probably won't need it. @cindex file names, restrict @cindex Windows file names @item --restrict-file-names=@var{mode} Change which characters found in remote URLs may show up in local file names generated from those URLs. Characters that are @dfn{restricted} by this option are escaped, i.e. replaced with @samp{%HH}, where @samp{HH} is the hexadecimal number that corresponds to the restricted character. By default, Wget escapes the characters that are not valid as part of file names on your operating system, as well as control characters that are typically unprintable. This option is useful for changing these defaults, either because you are downloading to a non-native partition, or because you want to disable escaping of the control characters. When mode is set to ``unix'', Wget escapes the character @samp{/} and the control characters in the ranges 0--31 and 128--159. This is the default on Unix-like OS'es. When mode is set to ``windows'', Wget escapes the characters @samp{\}, @samp{|}, @samp{/}, @samp{:}, @samp{?}, @samp{"}, @samp{*}, @samp{<}, @samp{>}, and the control characters in the ranges 0--31 and 128--159. In addition to this, Wget in Windows mode uses @samp{+} instead of @samp{:} to separate host and port in local file names, and uses @samp{@@} instead of @samp{?} to separate the query portion of the file name from the rest. Therefore, a URL that would be saved as @samp{www.xemacs.org:4300/search.pl?input=blah} in Unix mode would be saved as @samp{www.xemacs.org+4300/search.pl@@input=blah} in Windows mode. This mode is the default on Windows. If you append @samp{,nocontrol} to the mode, as in @samp{unix,nocontrol}, escaping of the control characters is also switched off. You can use @samp{--restrict-file-names=nocontrol} to turn off escaping of control characters without affecting the choice of the OS to use as file name restriction mode. @cindex IPv6 @itemx -4 @itemx --inet4-only @itemx -6 @itemx --inet6-only Force connecting to IPv4 or IPv6 addresses. With @samp{--inet4-only} or @samp{-4}, Wget will only connect to IPv4 hosts, ignoring AAAA records in DNS, and refusing to connect to IPv6 addresses specified in URLs. Conversely, with @samp{--inet6-only} or @samp{-6}, Wget will only connect to IPv6 hosts and ignore A records and IPv4 addresses. Neither options should be needed normally. By default, an IPv6-aware Wget will use the address family specified by the host's DNS record. If the DNS responds with both IPv4 and IPv6 addresses, Wget will them in sequence until it finds one it can connect to. (Also see @code{--prefer-family} option described below.) These options can be used to deliberately force the use of IPv4 or IPv6 address families on dual family systems, usually to aid debugging or to deal with broken network configuration. Only one of @samp{--inet6-only} and @samp{--inet4-only} may be specified at the same time. Neither option is available in Wget compiled without IPv6 support. @item --prefer-family=IPv4/IPv6/none When given a choice of several addresses, connect to the addresses with specified address family first. IPv4 addresses are preferred by default. This avoids spurious errors and connect attempts when accessing hosts that resolve to both IPv6 and IPv4 addresses from IPv4 networks. For example, @samp{www.kame.net} resolves to @samp{2001:200:0:8002:203:47ff:fea5:3085} and to @samp{203.178.141.194}. When the preferred family is @code{IPv4}, the IPv4 address is used first; when the preferred family is @code{IPv6}, the IPv6 address is used first; if the specified value is @code{none}, the address order returned by DNS is used without change. Unlike @samp{-4} and @samp{-6}, this option doesn't inhibit access to any address family, it only changes the @emph{order} in which the addresses are accessed. Also note that the reordering performed by this option is @dfn{stable}---it doesn't affect order of addresses of the same family. That is, the relative order of all IPv4 addresses and of all IPv6 addresses remains intact in all cases. @item --retry-connrefused Consider ``connection refused'' a transient error and try again. Normally Wget gives up on a URL when it is unable to connect to the site because failure to connect is taken as a sign that the server is not running at all and that retries would not help. This option is for mirroring unreliable sites whose servers tend to disappear for short periods of time. @cindex user @cindex password @cindex authentication @item --user=@var{user} @itemx --password=@var{password} Specify the username @var{user} and password @var{password} for both @sc{ftp} and @sc{http} file retrieval. These parameters can be overridden using the @samp{--ftp-user} and @samp{--ftp-password} options for @sc{ftp} connections and the @samp{--http-user} and @samp{--http-password} options for @sc{http} connections. @end table @node Directory Options @section Directory Options @table @samp @item -nd @itemx --no-directories Do not create a hierarchy of directories when retrieving recursively. With this option turned on, all files will get saved to the current directory, without clobbering (if a name shows up more than once, the filenames will get extensions @samp{.n}). @item -x @itemx --force-directories The opposite of @samp{-nd}---create a hierarchy of directories, even if one would not have been created otherwise. E.g. @samp{wget -x http://fly.srk.fer.hr/robots.txt} will save the downloaded file to @file{fly.srk.fer.hr/robots.txt}. @item -nH @itemx --no-host-directories Disable generation of host-prefixed directories. By default, invoking Wget with @samp{-r http://fly.srk.fer.hr/} will create a structure of directories beginning with @file{fly.srk.fer.hr/}. This option disables such behavior. @item --protocol-directories Use the protocol name as a directory component of local file names. For example, with this option, @samp{wget -r http://@var{host}} will save to @samp{http/@var{host}/...} rather than just to @samp{@var{host}/...}. @cindex cut directories @item --cut-dirs=@var{number} Ignore @var{number} directory components. This is useful for getting a fine-grained control over the directory where recursive retrieval will be saved. Take, for example, the directory at @samp{ftp://ftp.xemacs.org/pub/xemacs/}. If you retrieve it with @samp{-r}, it will be saved locally under @file{ftp.xemacs.org/pub/xemacs/}. While the @samp{-nH} option can remove the @file{ftp.xemacs.org/} part, you are still stuck with @file{pub/xemacs}. This is where @samp{--cut-dirs} comes in handy; it makes Wget not ``see'' @var{number} remote directory components. Here are several examples of how @samp{--cut-dirs} option works. @example @group No options -> ftp.xemacs.org/pub/xemacs/ -nH -> pub/xemacs/ -nH --cut-dirs=1 -> xemacs/ -nH --cut-dirs=2 -> . --cut-dirs=1 -> ftp.xemacs.org/xemacs/ ... @end group @end example If you just want to get rid of the directory structure, this option is similar to a combination of @samp{-nd} and @samp{-P}. However, unlike @samp{-nd}, @samp{--cut-dirs} does not lose with subdirectories---for instance, with @samp{-nH --cut-dirs=1}, a @file{beta/} subdirectory will be placed to @file{xemacs/beta}, as one would expect. @cindex directory prefix @item -P @var{prefix} @itemx --directory-prefix=@var{prefix} Set directory prefix to @var{prefix}. The @dfn{directory prefix} is the directory where all other files and subdirectories will be saved to, i.e. the top of the retrieval tree. The default is @samp{.} (the current directory). @end table @node HTTP Options @section HTTP Options @table @samp @cindex .html extension @item -E @itemx --html-extension If a file of type @samp{application/xhtml+xml} or @samp{text/html} is downloaded and the URL does not end with the regexp @samp{\.[Hh][Tt][Mm][Ll]?}, this option will cause the suffix @samp{.html} to be appended to the local filename. This is useful, for instance, when you're mirroring a remote site that uses @samp{.asp} pages, but you want the mirrored pages to be viewable on your stock Apache server. Another good use for this is when you're downloading CGI-generated materials. A URL like @samp{http://site.com/article.cgi?25} will be saved as @file{article.cgi?25.html}. Note that filenames changed in this way will be re-downloaded every time you re-mirror a site, because Wget can't tell that the local @file{@var{X}.html} file corresponds to remote URL @samp{@var{X}} (since it doesn't yet know that the URL produces output of type @samp{text/html} or @samp{application/xhtml+xml}. To prevent this re-downloading, you must use @samp{-k} and @samp{-K} so that the original version of the file will be saved as @file{@var{X}.orig} (@pxref{Recursive Retrieval Options}). @cindex http user @cindex http password @cindex authentication @item --http-user=@var{user} @itemx --http-password=@var{password} Specify the username @var{user} and password @var{password} on an @sc{http} server. According to the type of the challenge, Wget will encode them using either the @code{basic} (insecure) or the @code{digest} authentication scheme. Another way to specify username and password is in the @sc{url} itself (@pxref{URL Format}). Either method reveals your password to anyone who bothers to run @code{ps}. To prevent the passwords from being seen, store them in @file{.wgetrc} or @file{.netrc}, and make sure to protect those files from other users with @code{chmod}. If the passwords are really important, do not leave them lying in those files either---edit the files and delete them after Wget has started the download. @iftex For more information about security issues with Wget, @xref{Security Considerations}. @end iftex @cindex proxy @cindex cache @item --no-cache Disable server-side cache. In this case, Wget will send the remote server an appropriate directive (@samp{Pragma: no-cache}) to get the file from the remote service, rather than returning the cached version. This is especially useful for retrieving and flushing out-of-date documents on proxy servers. Caching is allowed by default. @cindex cookies @item --no-cookies Disable the use of cookies. Cookies are a mechanism for maintaining server-side state. The server sends the client a cookie using the @code{Set-Cookie} header, and the client responds with the same cookie upon further requests. Since cookies allow the server owners to keep track of visitors and for sites to exchange this information, some consider them a breach of privacy. The default is to use cookies; however, @emph{storing} cookies is not on by default. @cindex loading cookies @cindex cookies, loading @item --load-cookies @var{file} Load cookies from @var{file} before the first HTTP retrieval. @var{file} is a textual file in the format originally used by Netscape's @file{cookies.txt} file. You will typically use this option when mirroring sites that require that you be logged in to access some or all of their content. The login process typically works by the web server issuing an @sc{http} cookie upon receiving and verifying your credentials. The cookie is then resent by the browser when accessing that part of the site, and so proves your identity. Mirroring such a site requires Wget to send the same cookies your browser sends when communicating with the site. This is achieved by @samp{--load-cookies}---simply point Wget to the location of the @file{cookies.txt} file, and it will send the same cookies your browser would send in the same situation. Different browsers keep textual cookie files in different locations: @table @asis @item Netscape 4.x. The cookies are in @file{~/.netscape/cookies.txt}. @item Mozilla and Netscape 6.x. Mozilla's cookie file is also named @file{cookies.txt}, located somewhere under @file{~/.mozilla}, in the directory of your profile. The full path usually ends up looking somewhat like @file{~/.mozilla/default/@var{some-weird-string}/cookies.txt}. @item Internet Explorer. You can produce a cookie file Wget can use by using the File menu, Import and Export, Export Cookies. This has been tested with Internet Explorer 5; it is not guaranteed to work with earlier versions. @item Other browsers. If you are using a different browser to create your cookies, @samp{--load-cookies} will only work if you can locate or produce a cookie file in the Netscape format that Wget expects. @end table If you cannot use @samp{--load-cookies}, there might still be an alternative. If your browser supports a ``cookie manager'', you can use it to view the cookies used when accessing the site you're mirroring. Write down the name and value of the cookie, and manually instruct Wget to send those cookies, bypassing the ``official'' cookie support: @example wget --no-cookies --header "Cookie: @var{name}=@var{value}" @end example @cindex saving cookies @cindex cookies, saving @item --save-cookies @var{file} Save cookies to @var{file} before exiting. This will not save cookies that have expired or that have no expiry time (so-called ``session cookies''), but also see @samp{--keep-session-cookies}. @cindex cookies, session @cindex session cookies @item --keep-session-cookies When specified, causes @samp{--save-cookies} to also save session cookies. Session cookies are normally not saved because they are meant to be kept in memory and forgotten when you exit the browser. Saving them is useful on sites that require you to log in or to visit the home page before you can access some pages. With this option, multiple Wget runs are considered a single browser session as far as the site is concerned. Since the cookie file format does not normally carry session cookies, Wget marks them with an expiry timestamp of 0. Wget's @samp{--load-cookies} recognizes those as session cookies, but it might confuse other browsers. Also note that cookies so loaded will be treated as other session cookies, which means that if you want @samp{--save-cookies} to preserve them again, you must use @samp{--keep-session-cookies} again. @cindex Content-Length, ignore @cindex ignore length @item --ignore-length Unfortunately, some @sc{http} servers (@sc{cgi} programs, to be more precise) send out bogus @code{Content-Length} headers, which makes Wget go wild, as it thinks not all the document was retrieved. You can spot this syndrome if Wget retries getting the same document again and again, each time claiming that the (otherwise normal) connection has closed on the very same byte. With this option, Wget will ignore the @code{Content-Length} header---as if it never existed. @cindex header, add @item --header=@var{header-line} Send @var{header-line} along with the rest of the headers in each @sc{http} request. The supplied header is sent as-is, which means it must contain name and value separated by colon, and must not contain newlines. You may define more than one additional header by specifying @samp{--header} more than once. @example @group wget --header='Accept-Charset: iso-8859-2' \ --header='Accept-Language: hr' \ http://fly.srk.fer.hr/ @end group @end example Specification of an empty string as the header value will clear all previous user-defined headers. As of Wget 1.10, this option can be used to override headers otherwise generated automatically. This example instructs Wget to connect to localhost, but to specify @samp{foo.bar} in the @code{Host} header: @example wget --header="Host: foo.bar" http://localhost/ @end example In versions of Wget prior to 1.10 such use of @samp{--header} caused sending of duplicate headers. @cindex proxy user @cindex proxy password @cindex proxy authentication @item --proxy-user=@var{user} @itemx --proxy-password=@var{password} Specify the username @var{user} and password @var{password} for authentication on a proxy server. Wget will encode them using the @code{basic} authentication scheme. Security considerations similar to those with @samp{--http-password} pertain here as well. @cindex http referer @cindex referer, http @item --referer=@var{url} Include `Referer: @var{url}' header in HTTP request. Useful for retrieving documents with server-side processing that assume they are always being retrieved by interactive web browsers and only come out properly when Referer is set to one of the pages that point to them. @cindex server response, save @item --save-headers Save the headers sent by the @sc{http} server to the file, preceding the actual contents, with an empty line as the separator. @cindex user-agent @item -U @var{agent-string} @itemx --user-agent=@var{agent-string} Identify as @var{agent-string} to the @sc{http} server. The @sc{http} protocol allows the clients to identify themselves using a @code{User-Agent} header field. This enables distinguishing the @sc{www} software, usually for statistical purposes or for tracing of protocol violations. Wget normally identifies as @samp{Wget/@var{version}}, @var{version} being the current version number of Wget. However, some sites have been known to impose the policy of tailoring the output according to the @code{User-Agent}-supplied information. While this is not such a bad idea in theory, it has been abused by servers denying information to clients other than (historically) Netscape or, more frequently, Microsoft Internet Explorer. This option allows you to change the @code{User-Agent} line issued by Wget. Use of this option is discouraged, unless you really know what you are doing. Specifying empty user agent with @samp{--user-agent=""} instructs Wget not to send the @code{User-Agent} header in @sc{http} requests. @cindex POST @item --post-data=@var{string} @itemx --post-file=@var{file} Use POST as the method for all HTTP requests and send the specified data in the request body. @code{--post-data} sends @var{string} as data, whereas @code{--post-file} sends the contents of @var{file}. Other than that, they work in exactly the same way. Please be aware that Wget needs to know the size of the POST data in advance. Therefore the argument to @code{--post-file} must be a regular file; specifying a FIFO or something like @file{/dev/stdin} won't work. It's not quite clear how to work around this limitation inherent in HTTP/1.0. Although HTTP/1.1 introduces @dfn{chunked} transfer that doesn't require knowing the request length in advance, a client can't use chunked unless it knows it's talking to an HTTP/1.1 server. And it can't know that until it receives a response, which in turn requires the request to have been completed -- a chicken-and-egg problem. Note: if Wget is redirected after the POST request is completed, it will not send the POST data to the redirected URL. This is because URLs that process POST often respond with a redirection to a regular page, which does not desire or accept POST. It is not completely clear that this behavior is optimal; if it doesn't work out, it might be changed in the future. This example shows how to log to a server using POST and then proceed to download the desired pages, presumably only accessible to authorized users: @example @group # @r{Log in to the server. This can be done only once.} wget --save-cookies cookies.txt \ --post-data 'user=foo&password=bar' \ http://server.com/auth.php # @r{Now grab the page or pages we care about.} wget --load-cookies cookies.txt \ -p http://server.com/interesting/article.php @end group @end example If the server is using session cookies to track user authentication, the above will not work because @samp{--save-cookies} will not save them (and neither will browsers) and the @file{cookies.txt} file will be empty. In that case use @samp{--keep-session-cookies} along with @samp{--save-cookies} to force saving of session cookies. @end table @node HTTPS (SSL/TLS) Options @section HTTPS (SSL/TLS) Options @cindex SSL To support encrypted HTTP (HTTPS) downloads, Wget must be compiled with an external SSL library, currently OpenSSL. If Wget is compiled without SSL support, none of these options are available. @table @samp @cindex SSL protocol, choose @item --secure-protocol=@var{protocol} Choose the secure protocol to be used. Legal values are @samp{auto}, @samp{SSLv2}, @samp{SSLv3}, and @samp{TLSv1}. If @samp{auto} is used, the SSL library is given the liberty of choosing the appropriate protocol automatically, which is achieved by sending an SSLv2 greeting and announcing support for SSLv3 and TLSv1. This is the default. Specifying @samp{SSLv2}, @samp{SSLv3}, or @samp{TLSv1} forces the use of the corresponding protocol. This is useful when talking to old and buggy SSL server implementations that make it hard for OpenSSL to choose the correct protocol version. Fortunately, such servers are quite rare. @cindex SSL certificate, check @item --no-check-certificate Don't check the server certificate against the available certificate authorities. Also don't require the URL host name to match the common name presented by the certificate. As of Wget 1.10, the default is to verify the server's certificate against the recognized certificate authorities, breaking the SSL handshake and aborting the download if the verification fails. Although this provides more secure downloads, it does break interoperability with some sites that worked with previous Wget versions, particularly those using self-signed, expired, or otherwise invalid certificates. This option forces an ``insecure'' mode of operation that turns the certificate verification errors into warnings and allows you to proceed. If you encounter ``certificate verification'' errors or ones saying that ``common name doesn't match requested host name'', you can use this option to bypass the verification and proceed with the download. @emph{Only use this option if you are otherwise convinced of the site's authenticity, or if you really don't care about the validity of its certificate.} It is almost always a bad idea not to check the certificates when transmitting confidential or important data. @cindex SSL certificate @item --certificate=@var{file} Use the client certificate stored in @var{file}. This is needed for servers that are configured to require certificates from the clients that connect to them. Normally a certificate is not required and this switch is optional. @cindex SSL certificate type, specify @item --certificate-type=@var{type} Specify the type of the client certificate. Legal values are @samp{PEM} (assumed by default) and @samp{DER}, also known as @samp{ASN1}. @item --private-key=@var{file} Read the private key from @var{file}. This allows you to provide the private key in a file separate from the certificate. @item --private-key-type=@var{type} Specify the type of the private key. Accepted values are @samp{PEM} (the default) and @samp{DER}. @item --ca-certificate=@var{file} Use @var{file} as the file with the bundle of certificate authorities (``CA'') to verify the peers. The certificates must be in PEM format. Without this option Wget looks for CA certificates at the system-specified locations, chosen at OpenSSL installation time. @cindex SSL certificate authority @item --ca-directory=@var{directory} Specifies directory containing CA certificates in PEM format. Each file contains one CA certificate, and the file name is based on a hash value derived from the certificate. This is achieved by processing a certificate directory with the @code{c_rehash} utility supplied with OpenSSL. Using @samp{--ca-directory} is more efficient than @samp{--ca-certificate} when many certificates are installed because it allows Wget to fetch certificates on demand. Without this option Wget looks for CA certificates at the system-specified locations, chosen at OpenSSL installation time. @cindex entropy, specifying source of @cindex randomness, specifying source of @item --random-file=@var{file} Use @var{file} as the source of random data for seeding the pseudo-random number generator on systems without @file{/dev/random}. On such systems the SSL library needs an external source of randomness to initialize. Randomness may be provided by EGD (see @samp{--egd-file} below) or read from an external source specified by the user. If this option is not specified, Wget looks for random data in @code{$RANDFILE} or, if that is unset, in @file{$HOME/.rnd}. If none of those are available, it is likely that SSL encryption will not be usable. If you're getting the ``Could not seed OpenSSL PRNG; disabling SSL.'' error, you should provide random data using some of the methods described above. @cindex EGD @item --egd-file=@var{file} Use @var{file} as the EGD socket. EGD stands for @dfn{Entropy Gathering Daemon}, a user-space program that collects data from various unpredictable system sources and makes it available to other programs that might need it. Encryption software, such as the SSL library, needs sources of non-repeating randomness to seed the random number generator used to produce cryptographically strong keys. OpenSSL allows the user to specify his own source of entropy using the @code{RAND_FILE} environment variable. If this variable is unset, or if the specified file does not produce enough randomness, OpenSSL will read random data from EGD socket specified using this option. If this option is not specified (and the equivalent startup command is not used), EGD is never contacted. EGD is not needed on modern Unix systems that support @file{/dev/random}. @end table @node FTP Options @section FTP Options @table @samp @cindex ftp user @cindex ftp password @cindex ftp authentication @item --ftp-user=@var{user} @itemx --ftp-password=@var{password} Specify the username @var{user} and password @var{password} on an @sc{ftp} server. Without this, or the corresponding startup option, the password defaults to @samp{-wget@@}, normally used for anonymous FTP. Another way to specify username and password is in the @sc{url} itself (@pxref{URL Format}). Either method reveals your password to anyone who bothers to run @code{ps}. To prevent the passwords from being seen, store them in @file{.wgetrc} or @file{.netrc}, and make sure to protect those files from other users with @code{chmod}. If the passwords are really important, do not leave them lying in those files either---edit the files and delete them after Wget has started the download. @iftex For more information about security issues with Wget, @xref{Security Considerations}. @end iftex @cindex .listing files, removing @item --no-remove-listing Don't remove the temporary @file{.listing} files generated by @sc{ftp} retrievals. Normally, these files contain the raw directory listings received from @sc{ftp} servers. Not removing them can be useful for debugging purposes, or when you want to be able to easily check on the contents of remote server directories (e.g. to verify that a mirror you're running is complete). Note that even though Wget writes to a known filename for this file, this is not a security hole in the scenario of a user making @file{.listing} a symbolic link to @file{/etc/passwd} or something and asking @code{root} to run Wget in his or her directory. Depending on the options used, either Wget will refuse to write to @file{.listing}, making the globbing/recursion/time-stamping operation fail, or the symbolic link will be deleted and replaced with the actual @file{.listing} file, or the listing will be written to a @file{.listing.@var{number}} file. Even though this situation isn't a problem, though, @code{root} should never run Wget in a non-trusted user's directory. A user could do something as simple as linking @file{index.html} to @file{/etc/passwd} and asking @code{root} to run Wget with @samp{-N} or @samp{-r} so the file will be overwritten. @cindex globbing, toggle @item --no-glob Turn off @sc{ftp} globbing. Globbing refers to the use of shell-like special characters (@dfn{wildcards}), like @samp{*}, @samp{?}, @samp{[} and @samp{]} to retrieve more than one file from the same directory at once, like: @example wget ftp://gnjilux.srk.fer.hr/*.msg @end example By default, globbing will be turned on if the @sc{url} contains a globbing character. This option may be used to turn globbing on or off permanently. You may have to quote the @sc{url} to protect it from being expanded by your shell. Globbing makes Wget look for a directory listing, which is system-specific. This is why it currently works only with Unix @sc{ftp} servers (and the ones emulating Unix @code{ls} output). @cindex passive ftp @item --no-passive-ftp Disable the use of the @dfn{passive} FTP transfer mode. Passive FTP mandates that the client connect to the server to establish the data connection rather than the other way around. If the machine is connected to the Internet directly, both passive and active FTP should work equally well. Behind most firewall and NAT configurations passive FTP has a better chance of working. However, in some rare firewall configurations, active FTP actually works when passive FTP doesn't. If you suspect this to be the case, use this option, or set @code{passive_ftp=off} in your init file. @cindex symbolic links, retrieving @item --retr-symlinks Usually, when retrieving @sc{ftp} directories recursively and a symbolic link is encountered, the linked-to file is not downloaded. Instead, a matching symbolic link is created on the local filesystem. The pointed-to file will not be downloaded unless this recursive retrieval would have encountered it separately and downloaded it anyway. When @samp{--retr-symlinks} is specified, however, symbolic links are traversed and the pointed-to files are retrieved. At this time, this option does not cause Wget to traverse symlinks to directories and recurse through them, but in the future it should be enhanced to do this. Note that when retrieving a file (not a directory) because it was specified on the command-line, rather than because it was recursed to, this option has no effect. Symbolic links are always traversed in this case. @cindex Keep-Alive, turning off @cindex Persistent Connections, disabling @item --no-http-keep-alive Turn off the ``keep-alive'' feature for HTTP downloads. Normally, Wget asks the server to keep the connection open so that, when you download more than one document from the same server, they get transferred over the same TCP connection. This saves time and at the same time reduces the load on the server. This option is useful when, for some reason, persistent (keep-alive) connections don't work for you, for example due to a server bug or due to the inability of server-side scripts to cope with the connections. @end table @node Recursive Retrieval Options @section Recursive Retrieval Options @table @samp @item -r @itemx --recursive Turn on recursive retrieving. @xref{Recursive Download}, for more details. @item -l @var{depth} @itemx --level=@var{depth} Specify recursion maximum depth level @var{depth} (@pxref{Recursive Download}). The default maximum depth is 5. @cindex proxy filling @cindex delete after retrieval @cindex filling proxy cache @item --delete-after This option tells Wget to delete every single file it downloads, @emph{after} having done so. It is useful for pre-fetching popular pages through a proxy, e.g.: @example wget -r -nd --delete-after http://whatever.com/~popular/page/ @end example The @samp{-r} option is to retrieve recursively, and @samp{-nd} to not create directories. Note that @samp{--delete-after} deletes files on the local machine. It does not issue the @samp{DELE} command to remote FTP sites, for instance. Also note that when @samp{--delete-after} is specified, @samp{--convert-links} is ignored, so @samp{.orig} files are simply not created in the first place. @cindex conversion of links @cindex link conversion @item -k @itemx --convert-links After the download is complete, convert the links in the document to make them suitable for local viewing. This affects not only the visible hyperlinks, but any part of the document that links to external content, such as embedded images, links to style sheets, hyperlinks to non-@sc{html} content, etc. Each link will be changed in one of the two ways: @itemize @bullet @item The links to files that have been downloaded by Wget will be changed to refer to the file they point to as a relative link. Example: if the downloaded file @file{/foo/doc.html} links to @file{/bar/img.gif}, also downloaded, then the link in @file{doc.html} will be modified to point to @samp{../bar/img.gif}. This kind of transformation works reliably for arbitrary combinations of directories. @item The links to files that have not been downloaded by Wget will be changed to include host name and absolute path of the location they point to. Example: if the downloaded file @file{/foo/doc.html} links to @file{/bar/img.gif} (or to @file{../bar/img.gif}), then the link in @file{doc.html} will be modified to point to @file{http://@var{hostname}/bar/img.gif}. @end itemize Because of this, local browsing works reliably: if a linked file was downloaded, the link will refer to its local name; if it was not downloaded, the link will refer to its full Internet address rather than presenting a broken link. The fact that the former links are converted to relative links ensures that you can move the downloaded hierarchy to another directory. Note that only at the end of the download can Wget know which links have been downloaded. Because of that, the work done by @samp{-k} will be performed at the end of all the downloads. @cindex backing up converted files @item -K @itemx --backup-converted When converting a file, back up the original version with a @samp{.orig} suffix. Affects the behavior of @samp{-N} (@pxref{HTTP Time-Stamping Internals}). @item -m @itemx --mirror Turn on options suitable for mirroring. This option turns on recursion and time-stamping, sets infinite recursion depth and keeps @sc{ftp} directory listings. It is currently equivalent to @samp{-r -N -l inf --no-remove-listing}. @cindex page requisites @cindex required images, downloading @item -p @itemx --page-requisites This option causes Wget to download all the files that are necessary to properly display a given @sc{html} page. This includes such things as inlined images, sounds, and referenced stylesheets. Ordinarily, when downloading a single @sc{html} page, any requisite documents that may be needed to display it properly are not downloaded. Using @samp{-r} together with @samp{-l} can help, but since Wget does not ordinarily distinguish between external and inlined documents, one is generally left with ``leaf documents'' that are missing their requisites. For instance, say document @file{1.html} contains an @code{} tag referencing @file{1.gif} and an @code{} tag pointing to external document @file{2.html}. Say that @file{2.html} is similar but that its image is @file{2.gif} and it links to @file{3.html}. Say this continues up to some arbitrarily high number. If one executes the command: @example wget -r -l 2 http://@var{site}/1.html @end example then @file{1.html}, @file{1.gif}, @file{2.html}, @file{2.gif}, and @file{3.html} will be downloaded. As you can see, @file{3.html} is without its requisite @file{3.gif} because Wget is simply counting the number of hops (up to 2) away from @file{1.html} in order to determine where to stop the recursion. However, with this command: @example wget -r -l 2 -p http://@var{site}/1.html @end example all the above files @emph{and} @file{3.html}'s requisite @file{3.gif} will be downloaded. Similarly, @example wget -r -l 1 -p http://@var{site}/1.html @end example will cause @file{1.html}, @file{1.gif}, @file{2.html}, and @file{2.gif} to be downloaded. One might think that: @example wget -r -l 0 -p http://@var{site}/1.html @end example would download just @file{1.html} and @file{1.gif}, but unfortunately this is not the case, because @samp{-l 0} is equivalent to @samp{-l inf}---that is, infinite recursion. To download a single @sc{html} page (or a handful of them, all specified on the command-line or in a @samp{-i} @sc{url} input file) and its (or their) requisites, simply leave off @samp{-r} and @samp{-l}: @example wget -p http://@var{site}/1.html @end example Note that Wget will behave as if @samp{-r} had been specified, but only that single page and its requisites will be downloaded. Links from that page to external documents will not be followed. Actually, to download a single page and all its requisites (even if they exist on separate websites), and make sure the lot displays properly locally, this author likes to use a few options in addition to @samp{-p}: @example wget -E -H -k -K -p http://@var{site}/@var{document} @end example To finish off this topic, it's worth knowing that Wget's idea of an external document link is any URL specified in an @code{} tag, an @code{} tag, or a @code{} tag other than @code{}. @cindex @sc{html} comments @cindex comments, @sc{html} @item --strict-comments Turn on strict parsing of @sc{html} comments. The default is to terminate comments at the first occurrence of @samp{-->}. According to specifications, @sc{html} comments are expressed as @sc{sgml} @dfn{declarations}. Declaration is special markup that begins with @samp{}, such as @samp{}, that may contain comments between a pair of @samp{--} delimiters. @sc{html} comments are ``empty declarations'', @sc{sgml} declarations without any non-comment text. Therefore, @samp{} is a valid comment, and so is @samp{}, but @samp{} is not. On the other hand, most @sc{html} writers don't perceive comments as anything other than text delimited with @samp{}, which is not quite the same. For example, something like @samp{} works as a valid comment as long as the number of dashes is a multiple of four (!). If not, the comment technically lasts until the next @samp{--}, which may be at the other end of the document. Because of this, many popular browsers completely ignore the specification and implement what users have come to expect: comments delimited with @samp{}. Until version 1.9, Wget interpreted comments strictly, which resulted in missing links in many web pages that displayed fine in browsers, but had the misfortune of containing non-compliant comments. Beginning with version 1.9, Wget has joined the ranks of clients that implements ``naive'' comments, terminating each comment at the first occurrence of @samp{-->}. If, for whatever reason, you want strict comment parsing, use this option to turn it on. @end table @node Recursive Accept/Reject Options @section Recursive Accept/Reject Options @table @samp @item -A @var{acclist} --accept @var{acclist} @itemx -R @var{rejlist} --reject @var{rejlist} Specify comma-separated lists of file name suffixes or patterns to accept or reject (@pxref{Types of Files} for more details). @item -D @var{domain-list} @itemx --domains=@var{domain-list} Set domains to be followed. @var{domain-list} is a comma-separated list of domains. Note that it does @emph{not} turn on @samp{-H}. @item --exclude-domains @var{domain-list} Specify the domains that are @emph{not} to be followed. (@pxref{Spanning Hosts}). @cindex follow FTP links @item --follow-ftp Follow @sc{ftp} links from @sc{html} documents. Without this option, Wget will ignore all the @sc{ftp} links. @cindex tag-based recursive pruning @item --follow-tags=@var{list} Wget has an internal table of @sc{html} tag / attribute pairs that it considers when looking for linked documents during a recursive retrieval. If a user wants only a subset of those tags to be considered, however, he or she should be specify such tags in a comma-separated @var{list} with this option. @item --ignore-tags=@var{list} This is the opposite of the @samp{--follow-tags} option. To skip certain @sc{html} tags when recursively looking for documents to download, specify them in a comma-separated @var{list}. In the past, this option was the best bet for downloading a single page and its requisites, using a command-line like: @example wget --ignore-tags=a,area -H -k -K -r http://@var{site}/@var{document} @end example However, the author of this option came across a page with tags like @code{} and came to the realization that specifying tags to ignore was not enough. One can't just tell Wget to ignore @code{}, because then stylesheets will not be downloaded. Now the best bet for downloading a single page and its requisites is the dedicated @samp{--page-requisites} option. @item -H @itemx --span-hosts Enable spanning across hosts when doing recursive retrieving (@pxref{Spanning Hosts}). @item -L @itemx --relative Follow relative links only. Useful for retrieving a specific home page without any distractions, not even those from the same hosts (@pxref{Relative Links}). @item -I @var{list} @itemx --include-directories=@var{list} Specify a comma-separated list of directories you wish to follow when downloading (@pxref{Directory-Based Limits} for more details.) Elements of @var{list} may contain wildcards. @item -X @var{list} @itemx --exclude-directories=@var{list} Specify a comma-separated list of directories you wish to exclude from download (@pxref{Directory-Based Limits} for more details.) Elements of @var{list} may contain wildcards. @item -np @item --no-parent Do not ever ascend to the parent directory when retrieving recursively. This is a useful option, since it guarantees that only the files @emph{below} a certain hierarchy will be downloaded. @xref{Directory-Based Limits}, for more details. @end table @c man end @node Recursive Download @chapter Recursive Download @cindex recursion @cindex retrieving @cindex recursive download GNU Wget is capable of traversing parts of the Web (or a single @sc{http} or @sc{ftp} server), following links and directory structure. We refer to this as to @dfn{recursive retrieval}, or @dfn{recursion}. With @sc{http} @sc{url}s, Wget retrieves and parses the @sc{html} from the given @sc{url}, documents, retrieving the files the @sc{html} document was referring to, through markup like @code{href}, or @code{src}. If the freshly downloaded file is also of type @code{text/html} or @code{application/xhtml+xml}, it will be parsed and followed further. Recursive retrieval of @sc{http} and @sc{html} content is @dfn{breadth-first}. This means that Wget first downloads the requested @sc{html} document, then the documents linked from that document, then the documents linked by them, and so on. In other words, Wget first downloads the documents at depth 1, then those at depth 2, and so on until the specified maximum depth. The maximum @dfn{depth} to which the retrieval may descend is specified with the @samp{-l} option. The default maximum depth is five layers. When retrieving an @sc{ftp} @sc{url} recursively, Wget will retrieve all the data from the given directory tree (including the subdirectories up to the specified depth) on the remote server, creating its mirror image locally. @sc{ftp} retrieval is also limited by the @code{depth} parameter. Unlike @sc{http} recursion, @sc{ftp} recursion is performed depth-first. By default, Wget will create a local directory tree, corresponding to the one found on the remote server. Recursive retrieving can find a number of applications, the most important of which is mirroring. It is also useful for @sc{www} presentations, and any other opportunities where slow network connections should be bypassed by storing the files locally. You should be warned that recursive downloads can overload the remote servers. Because of that, many administrators frown upon them and may ban access from your site if they detect very fast downloads of big amounts of content. When downloading from Internet servers, consider using the @samp{-w} option to introduce a delay between accesses to the server. The download will take a while longer, but the server administrator will not be alarmed by your rudeness. Of course, recursive download may cause problems on your machine. If left to run unchecked, it can easily fill up the disk. If downloading from local network, it can also take bandwidth on the system, as well as consume memory and CPU. Try to specify the criteria that match the kind of download you are trying to achieve. If you want to download only one page, use @samp{--page-requisites} without any additional recursion. If you want to download things under one directory, use @samp{-np} to avoid downloading things from other directories. If you want to download all the files from one directory, use @samp{-l 1} to make sure the recursion depth never exceeds one. @xref{Following Links}, for more information about this. Recursive retrieval should be used with care. Don't say you were not warned. @node Following Links @chapter Following Links @cindex links @cindex following links When retrieving recursively, one does not wish to retrieve loads of unnecessary data. Most of the time the users bear in mind exactly what they want to download, and want Wget to follow only specific links. For example, if you wish to download the music archive from @samp{fly.srk.fer.hr}, you will not want to download all the home pages that happen to be referenced by an obscure part of the archive. Wget possesses several mechanisms that allows you to fine-tune which links it will follow. @menu * Spanning Hosts:: (Un)limiting retrieval based on host name. * Types of Files:: Getting only certain files. * Directory-Based Limits:: Getting only certain directories. * Relative Links:: Follow relative links only. * FTP Links:: Following FTP links. @end menu @node Spanning Hosts @section Spanning Hosts @cindex spanning hosts @cindex hosts, spanning Wget's recursive retrieval normally refuses to visit hosts different than the one you specified on the command line. This is a reasonable default; without it, every retrieval would have the potential to turn your Wget into a small version of google. However, visiting different hosts, or @dfn{host spanning,} is sometimes a useful option. Maybe the images are served from a different server. Maybe you're mirroring a site that consists of pages interlinked between three servers. Maybe the server has two equivalent names, and the @sc{html} pages refer to both interchangeably. @table @asis @item Span to any host---@samp{-H} The @samp{-H} option turns on host spanning, thus allowing Wget's recursive run to visit any host referenced by a link. Unless sufficient recursion-limiting criteria are applied depth, these foreign hosts will typically link to yet more hosts, and so on until Wget ends up sucking up much more data than you have intended. @item Limit spanning to certain domains---@samp{-D} The @samp{-D} option allows you to specify the domains that will be followed, thus limiting the recursion only to the hosts that belong to these domains. Obviously, this makes sense only in conjunction with @samp{-H}. A typical example would be downloading the contents of @samp{www.server.com}, but allowing downloads from @samp{images.server.com}, etc.: @example wget -rH -Dserver.com http://www.server.com/ @end example You can specify more than one address by separating them with a comma, e.g. @samp{-Ddomain1.com,domain2.com}. @item Keep download off certain domains---@samp{--exclude-domains} If there are domains you want to exclude specifically, you can do it with @samp{--exclude-domains}, which accepts the same type of arguments of @samp{-D}, but will @emph{exclude} all the listed domains. For example, if you want to download all the hosts from @samp{foo.edu} domain, with the exception of @samp{sunsite.foo.edu}, you can do it like this: @example wget -rH -Dfoo.edu --exclude-domains sunsite.foo.edu \ http://www.foo.edu/ @end example @end table @node Types of Files @section Types of Files @cindex types of files When downloading material from the web, you will often want to restrict the retrieval to only certain file types. For example, if you are interested in downloading @sc{gif}s, you will not be overjoyed to get loads of PostScript documents, and vice versa. Wget offers two options to deal with this problem. Each option description lists a short name, a long name, and the equivalent command in @file{.wgetrc}. @cindex accept wildcards @cindex accept suffixes @cindex wildcards, accept @cindex suffixes, accept @table @samp @item -A @var{acclist} @itemx --accept @var{acclist} @itemx accept = @var{acclist} The argument to @samp{--accept} option is a list of file suffixes or patterns that Wget will download during recursive retrieval. A suffix is the ending part of a file, and consists of ``normal'' letters, e.g. @samp{gif} or @samp{.jpg}. A matching pattern contains shell-like wildcards, e.g. @samp{books*} or @samp{zelazny*196[0-9]*}. So, specifying @samp{wget -A gif,jpg} will make Wget download only the files ending with @samp{gif} or @samp{jpg}, i.e. @sc{gif}s and @sc{jpeg}s. On the other hand, @samp{wget -A "zelazny*196[0-9]*"} will download only files beginning with @samp{zelazny} and containing numbers from 1960 to 1969 anywhere within. Look up the manual of your shell for a description of how pattern matching works. Of course, any number of suffixes and patterns can be combined into a comma-separated list, and given as an argument to @samp{-A}. @cindex reject wildcards @cindex reject suffixes @cindex wildcards, reject @cindex suffixes, reject @item -R @var{rejlist} @itemx --reject @var{rejlist} @itemx reject = @var{rejlist} The @samp{--reject} option works the same way as @samp{--accept}, only its logic is the reverse; Wget will download all files @emph{except} the ones matching the suffixes (or patterns) in the list. So, if you want to download a whole page except for the cumbersome @sc{mpeg}s and @sc{.au} files, you can use @samp{wget -R mpg,mpeg,au}. Analogously, to download all files except the ones beginning with @samp{bjork}, use @samp{wget -R "bjork*"}. The quotes are to prevent expansion by the shell. @end table The @samp{-A} and @samp{-R} options may be combined to achieve even better fine-tuning of which files to retrieve. E.g. @samp{wget -A "*zelazny*" -R .ps} will download all the files having @samp{zelazny} as a part of their name, but @emph{not} the PostScript files. Note that these two options do not affect the downloading of @sc{html} files; Wget must load all the @sc{html}s to know where to go at all---recursive retrieval would make no sense otherwise. @node Directory-Based Limits @section Directory-Based Limits @cindex directories @cindex directory limits Regardless of other link-following facilities, it is often useful to place the restriction of what files to retrieve based on the directories those files are placed in. There can be many reasons for this---the home pages may be organized in a reasonable directory structure; or some directories may contain useless information, e.g. @file{/cgi-bin} or @file{/dev} directories. Wget offers three different options to deal with this requirement. Each option description lists a short name, a long name, and the equivalent command in @file{.wgetrc}. @cindex directories, include @cindex include directories @cindex accept directories @table @samp @item -I @var{list} @itemx --include @var{list} @itemx include_directories = @var{list} @samp{-I} option accepts a comma-separated list of directories included in the retrieval. Any other directories will simply be ignored. The directories are absolute paths. So, if you wish to download from @samp{http://host/people/bozo/} following only links to bozo's colleagues in the @file{/people} directory and the bogus scripts in @file{/cgi-bin}, you can specify: @example wget -I /people,/cgi-bin http://host/people/bozo/ @end example @cindex directories, exclude @cindex exclude directories @cindex reject directories @item -X @var{list} @itemx --exclude @var{list} @itemx exclude_directories = @var{list} @samp{-X} option is exactly the reverse of @samp{-I}---this is a list of directories @emph{excluded} from the download. E.g. if you do not want Wget to download things from @file{/cgi-bin} directory, specify @samp{-X /cgi-bin} on the command line. The same as with @samp{-A}/@samp{-R}, these two options can be combined to get a better fine-tuning of downloading subdirectories. E.g. if you want to load all the files from @file{/pub} hierarchy except for @file{/pub/worthless}, specify @samp{-I/pub -X/pub/worthless}. @cindex no parent @item -np @itemx --no-parent @itemx no_parent = on The simplest, and often very useful way of limiting directories is disallowing retrieval of the links that refer to the hierarchy @dfn{above} than the beginning directory, i.e. disallowing ascent to the parent directory/directories. The @samp{--no-parent} option (short @samp{-np}) is useful in this case. Using it guarantees that you will never leave the existing hierarchy. Supposing you issue Wget with: @example wget -r --no-parent http://somehost/~luzer/my-archive/ @end example You may rest assured that none of the references to @file{/~his-girls-homepage/} or @file{/~luzer/all-my-mpegs/} will be followed. Only the archive you are interested in will be downloaded. Essentially, @samp{--no-parent} is similar to @samp{-I/~luzer/my-archive}, only it handles redirections in a more intelligent fashion. @end table @node Relative Links @section Relative Links @cindex relative links When @samp{-L} is turned on, only the relative links are ever followed. Relative links are here defined those that do not refer to the web server root. For example, these links are relative: @example @end example These links are not relative: @example @end example Using this option guarantees that recursive retrieval will not span hosts, even without @samp{-H}. In simple cases it also allows downloads to ``just work'' without having to convert links. This option is probably not very useful and might be removed in a future release. @node FTP Links @section Following FTP Links @cindex following ftp links The rules for @sc{ftp} are somewhat specific, as it is necessary for them to be. @sc{ftp} links in @sc{html} documents are often included for purposes of reference, and it is often inconvenient to download them by default. To have @sc{ftp} links followed from @sc{html} documents, you need to specify the @samp{--follow-ftp} option. Having done that, @sc{ftp} links will span hosts regardless of @samp{-H} setting. This is logical, as @sc{ftp} links rarely point to the same host where the @sc{http} server resides. For similar reasons, the @samp{-L} options has no effect on such downloads. On the other hand, domain acceptance (@samp{-D}) and suffix rules (@samp{-A} and @samp{-R}) apply normally. Also note that followed links to @sc{ftp} directories will not be retrieved recursively further. @node Time-Stamping @chapter Time-Stamping @cindex time-stamping @cindex timestamping @cindex updating the archives @cindex incremental updating One of the most important aspects of mirroring information from the Internet is updating your archives. Downloading the whole archive again and again, just to replace a few changed files is expensive, both in terms of wasted bandwidth and money, and the time to do the update. This is why all the mirroring tools offer the option of incremental updating. Such an updating mechanism means that the remote server is scanned in search of @dfn{new} files. Only those new files will be downloaded in the place of the old ones. A file is considered new if one of these two conditions are met: @enumerate @item A file of that name does not already exist locally. @item A file of that name does exist, but the remote file was modified more recently than the local file. @end enumerate To implement this, the program needs to be aware of the time of last modification of both local and remote files. We call this information the @dfn{time-stamp} of a file. The time-stamping in GNU Wget is turned on using @samp{--timestamping} (@samp{-N}) option, or through @code{timestamping = on} directive in @file{.wgetrc}. With this option, for each file it intends to download, Wget will check whether a local file of the same name exists. If it does, and the remote file is older, Wget will not download it. If the local file does not exist, or the sizes of the files do not match, Wget will download the remote file no matter what the time-stamps say. @menu * Time-Stamping Usage:: * HTTP Time-Stamping Internals:: * FTP Time-Stamping Internals:: @end menu @node Time-Stamping Usage @section Time-Stamping Usage @cindex time-stamping usage @cindex usage, time-stamping The usage of time-stamping is simple. Say you would like to download a file so that it keeps its date of modification. @example wget -S http://www.gnu.ai.mit.edu/ @end example A simple @code{ls -l} shows that the time stamp on the local file equals the state of the @code{Last-Modified} header, as returned by the server. As you can see, the time-stamping info is preserved locally, even without @samp{-N} (at least for @sc{http}). Several days later, you would like Wget to check if the remote file has changed, and download it if it has. @example wget -N http://www.gnu.ai.mit.edu/ @end example Wget will ask the server for the last-modified date. If the local file has the same timestamp as the server, or a newer one, the remote file will not be re-fetched. However, if the remote file is more recent, Wget will proceed to fetch it. The same goes for @sc{ftp}. For example: @example wget "ftp://ftp.ifi.uio.no/pub/emacs/gnus/*" @end example (The quotes around that URL are to prevent the shell from trying to interpret the @samp{*}.) After download, a local directory listing will show that the timestamps match those on the remote server. Reissuing the command with @samp{-N} will make Wget re-fetch @emph{only} the files that have been modified since the last download. If you wished to mirror the GNU archive every week, you would use a command like the following, weekly: @example wget --timestamping -r ftp://ftp.gnu.org/pub/gnu/ @end example Note that time-stamping will only work for files for which the server gives a timestamp. For @sc{http}, this depends on getting a @code{Last-Modified} header. For @sc{ftp}, this depends on getting a directory listing with dates in a format that Wget can parse (@pxref{FTP Time-Stamping Internals}). @node HTTP Time-Stamping Internals @section HTTP Time-Stamping Internals @cindex http time-stamping Time-stamping in @sc{http} is implemented by checking of the @code{Last-Modified} header. If you wish to retrieve the file @file{foo.html} through @sc{http}, Wget will check whether @file{foo.html} exists locally. If it doesn't, @file{foo.html} will be retrieved unconditionally. If the file does exist locally, Wget will first check its local time-stamp (similar to the way @code{ls -l} checks it), and then send a @code{HEAD} request to the remote server, demanding the information on the remote file. The @code{Last-Modified} header is examined to find which file was modified more recently (which makes it ``newer''). If the remote file is newer, it will be downloaded; if it is older, Wget will give up.@footnote{As an additional check, Wget will look at the @code{Content-Length} header, and compare the sizes; if they are not the same, the remote file will be downloaded no matter what the time-stamp says.} When @samp{--backup-converted} (@samp{-K}) is specified in conjunction with @samp{-N}, server file @samp{@var{X}} is compared to local file @samp{@var{X}.orig}, if extant, rather than being compared to local file @samp{@var{X}}, which will always differ if it's been converted by @samp{--convert-links} (@samp{-k}). Arguably, @sc{http} time-stamping should be implemented using the @code{If-Modified-Since} request. @node FTP Time-Stamping Internals @section FTP Time-Stamping Internals @cindex ftp time-stamping In theory, @sc{ftp} time-stamping works much the same as @sc{http}, only @sc{ftp} has no headers---time-stamps must be ferreted out of directory listings. If an @sc{ftp} download is recursive or uses globbing, Wget will use the @sc{ftp} @code{LIST} command to get a file listing for the directory containing the desired file(s). It will try to analyze the listing, treating it like Unix @code{ls -l} output, extracting the time-stamps. The rest is exactly the same as for @sc{http}. Note that when retrieving individual files from an @sc{ftp} server without using globbing or recursion, listing files will not be downloaded (and thus files will not be time-stamped) unless @samp{-N} is specified. Assumption that every directory listing is a Unix-style listing may sound extremely constraining, but in practice it is not, as many non-Unix @sc{ftp} servers use the Unixoid listing format because most (all?) of the clients understand it. Bear in mind that @sc{rfc959} defines no standard way to get a file list, let alone the time-stamps. We can only hope that a future standard will define this. Another non-standard solution includes the use of @code{MDTM} command that is supported by some @sc{ftp} servers (including the popular @code{wu-ftpd}), which returns the exact time of the specified file. Wget may support this command in the future. @node Startup File @chapter Startup File @cindex startup file @cindex wgetrc @cindex .wgetrc @cindex startup @cindex .netrc Once you know how to change default settings of Wget through command line arguments, you may wish to make some of those settings permanent. You can do that in a convenient way by creating the Wget startup file---@file{.wgetrc}. Besides @file{.wgetrc} is the ``main'' initialization file, it is convenient to have a special facility for storing passwords. Thus Wget reads and interprets the contents of @file{$HOME/.netrc}, if it finds it. You can find @file{.netrc} format in your system manuals. Wget reads @file{.wgetrc} upon startup, recognizing a limited set of commands. @menu * Wgetrc Location:: Location of various wgetrc files. * Wgetrc Syntax:: Syntax of wgetrc. * Wgetrc Commands:: List of available commands. * Sample Wgetrc:: A wgetrc example. @end menu @node Wgetrc Location @section Wgetrc Location @cindex wgetrc location @cindex location of wgetrc When initializing, Wget will look for a @dfn{global} startup file, @file{/usr/local/etc/wgetrc} by default (or some prefix other than @file{/usr/local}, if Wget was not installed there) and read commands from there, if it exists. Then it will look for the user's file. If the environmental variable @code{WGETRC} is set, Wget will try to load that file. Failing that, no further attempts will be made. If @code{WGETRC} is not set, Wget will try to load @file{$HOME/.wgetrc}. The fact that user's settings are loaded after the system-wide ones means that in case of collision user's wgetrc @emph{overrides} the system-wide wgetrc (in @file{/usr/local/etc/wgetrc} by default). Fascist admins, away! @node Wgetrc Syntax @section Wgetrc Syntax @cindex wgetrc syntax @cindex syntax of wgetrc The syntax of a wgetrc command is simple: @example variable = value @end example The @dfn{variable} will also be called @dfn{command}. Valid @dfn{values} are different for different commands. The commands are case-insensitive and underscore-insensitive. Thus @samp{DIr__PrefiX} is the same as @samp{dirprefix}. Empty lines, lines beginning with @samp{#} and lines containing white-space only are discarded. Commands that expect a comma-separated list will clear the list on an empty command. So, if you wish to reset the rejection list specified in global @file{wgetrc}, you can do it with: @example reject = @end example @node Wgetrc Commands @section Wgetrc Commands @cindex wgetrc commands The complete set of commands is listed below. Legal values are listed after the @samp{=}. Simple Boolean values can be set or unset using @samp{on} and @samp{off} or @samp{1} and @samp{0}. Some commands take pseudo-arbitrary values. @var{address} values can be hostnames or dotted-quad IP addresses. @var{n} can be any positive integer, or @samp{inf} for infinity, where appropriate. @var{string} values can be any non-empty string. Most of these commands have direct command-line equivalents. Also, any wgetrc command can be specified on the command line using the @samp{--execute} switch (@pxref{Basic Startup Options}.) @table @asis @item accept/reject = @var{string} Same as @samp{-A}/@samp{-R} (@pxref{Types of Files}). @item add_hostdir = on/off Enable/disable host-prefixed file names. @samp{-nH} disables it. @item continue = on/off If set to on, force continuation of preexistent partially retrieved files. See @samp{-c} before setting it. @item background = on/off Enable/disable going to background---the same as @samp{-b} (which enables it). @item backup_converted = on/off Enable/disable saving pre-converted files with the suffix @samp{.orig}---the same as @samp{-K} (which enables it). @c @item backups = @var{number} @c #### Document me! @c @item base = @var{string} Consider relative @sc{url}s in @sc{url} input files forced to be interpreted as @sc{html} as being relative to @var{string}---the same as @samp{--base=@var{string}}. @item bind_address = @var{address} Bind to @var{address}, like the @samp{--bind-address=@var{address}}. @item ca_certificate = @var{file} Set the certificate authority bundle file to @var{file}. The same as @samp{--ca-certificate=@var{file}}. @item ca_directory = @var{directory} Set the directory used for certificate authorities. The same as @samp{--ca-directory=@var{directory}}. @item cache = on/off When set to off, disallow server-caching. See the @samp{--no-cache} option. @item certificate = @var{file} Set the client certificate file name to @var{file}. The same as @samp{--certificate=@var{file}}. @item certificate_type = @var{string} Specify the type of the client certificate, legal values being @samp{PEM} (the default) and @samp{DER} (aka ASN1). The same as @samp{--certificate-type=@var{string}}. @item check_certificate = on/off If this is set to off, the server certificate is not checked against the specified client authorities. The default is ``on''. The same as @samp{--check-certificate}. @item convert_links = on/off Convert non-relative links locally. The same as @samp{-k}. @item cookies = on/off When set to off, disallow cookies. See the @samp{--cookies} option. @item connect_timeout = @var{n} Set the connect timeout---the same as @samp{--connect-timeout}. @item cut_dirs = @var{n} Ignore @var{n} remote directory components. Equivalent to @samp{--cut-dirs=@var{n}}. @item debug = on/off Debug mode, same as @samp{-d}. @item delete_after = on/off Delete after download---the same as @samp{--delete-after}. @item dir_prefix = @var{string} Top of directory tree---the same as @samp{-P @var{string}}. @item dirstruct = on/off Turning dirstruct on or off---the same as @samp{-x} or @samp{-nd}, respectively. @item dns_cache = on/off Turn DNS caching on/off. Since DNS caching is on by default, this option is normally used to turn it off and is equivalent to @samp{--no-dns-cache}. @item dns_timeout = @var{n} Set the DNS timeout---the same as @samp{--dns-timeout}. @item domains = @var{string} Same as @samp{-D} (@pxref{Spanning Hosts}). @item dot_bytes = @var{n} Specify the number of bytes ``contained'' in a dot, as seen throughout the retrieval (1024 by default). You can postfix the value with @samp{k} or @samp{m}, representing kilobytes and megabytes, respectively. With dot settings you can tailor the dot retrieval to suit your needs, or you can use the predefined @dfn{styles} (@pxref{Download Options}). @item dots_in_line = @var{n} Specify the number of dots that will be printed in each line throughout the retrieval (50 by default). @item dot_spacing = @var{n} Specify the number of dots in a single cluster (10 by default). @item egd_file = @var{file} Use @var{string} as the EGD socket file name. The same as @samp{--egd-file=@var{file}}. @item exclude_directories = @var{string} Specify a comma-separated list of directories you wish to exclude from download---the same as @samp{-X @var{string}} (@pxref{Directory-Based Limits}). @item exclude_domains = @var{string} Same as @samp{--exclude-domains=@var{string}} (@pxref{Spanning Hosts}). @item follow_ftp = on/off Follow @sc{ftp} links from @sc{html} documents---the same as @samp{--follow-ftp}. @item follow_tags = @var{string} Only follow certain @sc{html} tags when doing a recursive retrieval, just like @samp{--follow-tags=@var{string}}. @item force_html = on/off If set to on, force the input filename to be regarded as an @sc{html} document---the same as @samp{-F}. @item ftp_password = @var{string} Set your @sc{ftp} password to @var{string}. Without this setting, the password defaults to @samp{-wget@@}, which is a useful default for anonymous @sc{ftp} access. This command used to be named @code{passwd} prior to Wget 1.10. @item ftp_proxy = @var{string} Use @var{string} as @sc{ftp} proxy, instead of the one specified in environment. @item ftp_user = @var{string} Set @sc{ftp} user to @var{string}. This command used to be named @code{login} prior to Wget 1.10. @item glob = on/off Turn globbing on/off---the same as @samp{--glob} and @samp{--no-glob}. @item header = @var{string} Define a header for HTTP doewnloads, like using @samp{--header=@var{string}}. @item html_extension = on/off Add a @samp{.html} extension to @samp{text/html} or @samp{application/xhtml+xml} files without it, like @samp{-E}. @item http_keep_alive = on/off Turn the keep-alive feature on or off (defaults to on). Turning it off is equivalent to @samp{--no-http-keep-alive}. @item http_password = @var{string} Set @sc{http} password, equivalent to @samp{--http-password=@var{string}}. @item http_proxy = @var{string} Use @var{string} as @sc{http} proxy, instead of the one specified in environment. @item http_user = @var{string} Set @sc{http} user to @var{string}, equivalent to @samp{--http-user=@var{string}}. @item ignore_length = on/off When set to on, ignore @code{Content-Length} header; the same as @samp{--ignore-length}. @item ignore_tags = @var{string} Ignore certain @sc{html} tags when doing a recursive retrieval, like @samp{--ignore-tags=@var{string}}. @item include_directories = @var{string} Specify a comma-separated list of directories you wish to follow when downloading---the same as @samp{-I @var{string}}. @item inet4_only = on/off Force connecting to IPv4 addresses, off by default. You can put this in the global init file to disable Wget's attempts to resolve and connect to IPv6 hosts. Available only if Wget was compiled with IPv6 support. The same as @samp{--inet4-only} or @samp{-4}. @item inet6_only = on/off Force connecting to IPv6 addresses, off by default. Available only if Wget was compiled with IPv6 support. The same as @samp{--inet6-only} or @samp{-6}. @item input = @var{file} Read the @sc{url}s from @var{string}, like @samp{-i @var{file}}. @item kill_longer = on/off Consider data longer than specified in content-length header as invalid (and retry getting it). The default behavior is to save as much data as there is, provided there is more than or equal to the value in @code{Content-Length}. @item limit_rate = @var{rate} Limit the download speed to no more than @var{rate} bytes per second. The same as @samp{--limit-rate=@var{rate}}. @item load_cookies = @var{file} Load cookies from @var{file}. See @samp{--load-cookies @var{file}}. @item logfile = @var{file} Set logfile to @var{file}, the same as @samp{-o @var{file}}. @item mirror = on/off Turn mirroring on/off. The same as @samp{-m}. @item netrc = on/off Turn reading netrc on or off. @item noclobber = on/off Same as @samp{-nc}. @item no_parent = on/off Disallow retrieving outside the directory hierarchy, like @samp{--no-parent} (@pxref{Directory-Based Limits}). @item no_proxy = @var{string} Use @var{string} as the comma-separated list of domains to avoid in proxy loading, instead of the one specified in environment. @item output_document = @var{file} Set the output filename---the same as @samp{-O @var{file}}. @item page_requisites = on/off Download all ancillary documents necessary for a single @sc{html} page to display properly---the same as @samp{-p}. @item passive_ftp = on/off Change setting of passive @sc{ftp}, equivalent to the @samp{--passive-ftp} option. @itemx password = @var{string} Specify password @var{string} for both @sc{ftp} and @sc{http} file retrieval. This command can be overridden using the @samp{ftp_password} and @samp{http_password} command for @sc{ftp} and @sc{http} respectively. @item post_data = @var{string} Use POST as the method for all HTTP requests and send @var{string} in the request body. The same as @samp{--post-data=@var{string}}. @item post_file = @var{file} Use POST as the method for all HTTP requests and send the contents of @var{file} in the request body. The same as @samp{--post-file=@var{file}}. @item prefer_family = IPv4/IPv6/none When given a choice of several addresses, connect to the addresses with specified address family first. IPv4 addresses are preferred by default. The same as @samp{--prefer-family}, which see for a detailed discussion of why this is useful. @item private_key = @var{file} Set the private key file to @var{file}. The same as @samp{--private-key=@var{file}}. @item private_key_type = @var{string} Specify the type of the private key, legal values being @samp{PEM} (the default) and @samp{DER} (aka ASN1). The same as @samp{--private-type=@var{string}}. @item progress = @var{string} Set the type of the progress indicator. Legal types are @samp{dot} and @samp{bar}. Equivalent to @samp{--progress=@var{string}}. @item protocol_directories = on/off When set, use the protocol name as a directory component of local file names. The same as @samp{--protocol-directories}. @item proxy_user = @var{string} Set proxy authentication user name to @var{string}, like @samp{--proxy-user=@var{string}}. @item proxy_password = @var{string} Set proxy authentication password to @var{string}, like @samp{--proxy-password=@var{string}}. @item quiet = on/off Quiet mode---the same as @samp{-q}. @item quota = @var{quota} Specify the download quota, which is useful to put in the global @file{wgetrc}. When download quota is specified, Wget will stop retrieving after the download sum has become greater than quota. The quota can be specified in bytes (default), kbytes @samp{k} appended) or mbytes (@samp{m} appended). Thus @samp{quota = 5m} will set the quota to 5 megabytes. Note that the user's startup file overrides system settings. @item random_file = @var{file} Use @var{file} as a source of randomness on systems lacking @file{/dev/random}. @item read_timeout = @var{n} Set the read (and write) timeout---the same as @samp{--read-timeout=@var{n}}. @item reclevel = @var{n} Recursion level (depth)---the same as @samp{-l @var{n}}. @item recursive = on/off Recursive on/off---the same as @samp{-r}. @item referer = @var{string} Set HTTP @samp{Referer:} header just like @samp{--referer=@var{string}}. (Note it was the folks who wrote the @sc{http} spec who got the spelling of ``referrer'' wrong.) @item relative_only = on/off Follow only relative links---the same as @samp{-L} (@pxref{Relative Links}). @item remove_listing = on/off If set to on, remove @sc{ftp} listings downloaded by Wget. Setting it to off is the same as @samp{--no-remove-listing}. @item restrict_file_names = unix/windows Restrict the file names generated by Wget from URLs. See @samp{--restrict-file-names} for a more detailed description. @item retr_symlinks = on/off When set to on, retrieve symbolic links as if they were plain files; the same as @samp{--retr-symlinks}. @item retry_connrefused = on/off When set to on, consider ``connection refused'' a transient error---the same as @samp{--retry-connrefused}. @item robots = on/off Specify whether the norobots convention is respected by Wget, ``on'' by default. This switch controls both the @file{/robots.txt} and the @samp{nofollow} aspect of the spec. @xref{Robot Exclusion}, for more details about this. Be sure you know what you are doing before turning this off. @item save_cookies = @var{file} Save cookies to @var{file}. The same as @samp{--save-cookies @var{file}}. @item secure_protocol = @var{string} Choose the secure protocol to be used. Legal values are @samp{auto} (the default), @samp{SSLv2}, @samp{SSLv3}, and @samp{TLSv1}. The same as @samp{--secure-protocol=@var{string}}. @item server_response = on/off Choose whether or not to print the @sc{http} and @sc{ftp} server responses---the same as @samp{-S}. @item span_hosts = on/off Same as @samp{-H}. @item strict_comments = on/off Same as @samp{--strict-comments}. @item timeout = @var{n} Set all applicable timeout values to @var{n}, the same as @samp{-T @var{n}}. @item timestamping = on/off Turn timestamping on/off. The same as @samp{-N} (@pxref{Time-Stamping}). @item tries = @var{n} Set number of retries per @sc{url}---the same as @samp{-t @var{n}}. @item use_proxy = on/off When set to off, don't use proxy even when proxy-related environment variables are set. In that case it is the same as using @samp{--no-proxy}. @item user = @var{string} Specify username @var{string} for both @sc{ftp} and @sc{http} file retrieval. This command can be overridden using the @samp{ftp_user} and @samp{http_user} command for @sc{ftp} and @sc{http} respectively. @item verbose = on/off Turn verbose on/off---the same as @samp{-v}/@samp{-nv}. @item wait = @var{n} Wait @var{n} seconds between retrievals---the same as @samp{-w @var{n}}. @item waitretry = @var{n} Wait up to @var{n} seconds between retries of failed retrievals only---the same as @samp{--waitretry=@var{n}}. Note that this is turned on by default in the global @file{wgetrc}. @item randomwait = on/off Turn random between-request wait times on or off. The same as @samp{--random-wait}. @end table @node Sample Wgetrc @section Sample Wgetrc @cindex sample wgetrc This is the sample initialization file, as given in the distribution. It is divided in two section---one for global usage (suitable for global startup file), and one for local usage (suitable for @file{$HOME/.wgetrc}). Be careful about the things you change. Note that almost all the lines are commented out. For a command to have any effect, you must remove the @samp{#} character at the beginning of its line. @example @include sample.wgetrc.munged_for_texi_inclusion @end example @node Examples @chapter Examples @cindex examples @c man begin EXAMPLES The examples are divided into three sections loosely based on their complexity. @menu * Simple Usage:: Simple, basic usage of the program. * Advanced Usage:: Advanced tips. * Very Advanced Usage:: The hairy stuff. @end menu @node Simple Usage @section Simple Usage @itemize @bullet @item Say you want to download a @sc{url}. Just type: @example wget http://fly.srk.fer.hr/ @end example @item But what will happen if the connection is slow, and the file is lengthy? The connection will probably fail before the whole file is retrieved, more than once. In this case, Wget will try getting the file until it either gets the whole of it, or exceeds the default number of retries (this being 20). It is easy to change the number of tries to 45, to insure that the whole file will arrive safely: @example wget --tries=45 http://fly.srk.fer.hr/jpg/flyweb.jpg @end example @item Now let's leave Wget to work in the background, and write its progress to log file @file{log}. It is tiring to type @samp{--tries}, so we shall use @samp{-t}. @example wget -t 45 -o log http://fly.srk.fer.hr/jpg/flyweb.jpg & @end example The ampersand at the end of the line makes sure that Wget works in the background. To unlimit the number of retries, use @samp{-t inf}. @item The usage of @sc{ftp} is as simple. Wget will take care of login and password. @example wget ftp://gnjilux.srk.fer.hr/welcome.msg @end example @item If you specify a directory, Wget will retrieve the directory listing, parse it and convert it to @sc{html}. Try: @example wget ftp://ftp.gnu.org/pub/gnu/ links index.html @end example @end itemize @node Advanced Usage @section Advanced Usage @itemize @bullet @item You have a file that contains the URLs you want to download? Use the @samp{-i} switch: @example wget -i @var{file} @end example If you specify @samp{-} as file name, the @sc{url}s will be read from standard input. @item Create a five levels deep mirror image of the GNU web site, with the same directory structure the original has, with only one try per document, saving the log of the activities to @file{gnulog}: @example wget -r http://www.gnu.org/ -o gnulog @end example @item The same as the above, but convert the links in the @sc{html} files to point to local files, so you can view the documents off-line: @example wget --convert-links -r http://www.gnu.org/ -o gnulog @end example @item Retrieve only one @sc{html} page, but make sure that all the elements needed for the page to be displayed, such as inline images and external style sheets, are also downloaded. Also make sure the downloaded page references the downloaded links. @example wget -p --convert-links http://www.server.com/dir/page.html @end example The @sc{html} page will be saved to @file{www.server.com/dir/page.html}, and the images, stylesheets, etc., somewhere under @file{www.server.com/}, depending on where they were on the remote server. @item The same as the above, but without the @file{www.server.com/} directory. In fact, I don't want to have all those random server directories anyway---just save @emph{all} those files under a @file{download/} subdirectory of the current directory. @example wget -p --convert-links -nH -nd -Pdownload \ http://www.server.com/dir/page.html @end example @item Retrieve the index.html of @samp{www.lycos.com}, showing the original server headers: @example wget -S http://www.lycos.com/ @end example @item Save the server headers with the file, perhaps for post-processing. @example wget --save-headers http://www.lycos.com/ more index.html @end example @item Retrieve the first two levels of @samp{wuarchive.wustl.edu}, saving them to @file{/tmp}. @example wget -r -l2 -P/tmp ftp://wuarchive.wustl.edu/ @end example @item You want to download all the @sc{gif}s from a directory on an @sc{http} server. You tried @samp{wget http://www.server.com/dir/*.gif}, but that didn't work because @sc{http} retrieval does not support globbing. In that case, use: @example wget -r -l1 --no-parent -A.gif http://www.server.com/dir/ @end example More verbose, but the effect is the same. @samp{-r -l1} means to retrieve recursively (@pxref{Recursive Download}), with maximum depth of 1. @samp{--no-parent} means that references to the parent directory are ignored (@pxref{Directory-Based Limits}), and @samp{-A.gif} means to download only the @sc{gif} files. @samp{-A "*.gif"} would have worked too. @item Suppose you were in the middle of downloading, when Wget was interrupted. Now you do not want to clobber the files already present. It would be: @example wget -nc -r http://www.gnu.org/ @end example @item If you want to encode your own username and password to @sc{http} or @sc{ftp}, use the appropriate @sc{url} syntax (@pxref{URL Format}). @example wget ftp://hniksic:mypassword@@unix.server.com/.emacs @end example Note, however, that this usage is not advisable on multi-user systems because it reveals your password to anyone who looks at the output of @code{ps}. @cindex redirecting output @item You would like the output documents to go to standard output instead of to files? @example wget -O - http://jagor.srce.hr/ http://www.srce.hr/ @end example You can also combine the two options and make pipelines to retrieve the documents from remote hotlists: @example wget -O - http://cool.list.com/ | wget --force-html -i - @end example @end itemize @node Very Advanced Usage @section Very Advanced Usage @cindex mirroring @itemize @bullet @item If you wish Wget to keep a mirror of a page (or @sc{ftp} subdirectories), use @samp{--mirror} (@samp{-m}), which is the shorthand for @samp{-r -l inf -N}. You can put Wget in the crontab file asking it to recheck a site each Sunday: @example crontab 0 0 * * 0 wget --mirror http://www.gnu.org/ -o /home/me/weeklog @end example @item In addition to the above, you want the links to be converted for local viewing. But, after having read this manual, you know that link conversion doesn't play well with timestamping, so you also want Wget to back up the original @sc{html} files before the conversion. Wget invocation would look like this: @example wget --mirror --convert-links --backup-converted \ http://www.gnu.org/ -o /home/me/weeklog @end example @item But you've also noticed that local viewing doesn't work all that well when @sc{html} files are saved under extensions other than @samp{.html}, perhaps because they were served as @file{index.cgi}. So you'd like Wget to rename all the files served with content-type @samp{text/html} or @samp{application/xhtml+xml} to @file{@var{name}.html}. @example wget --mirror --convert-links --backup-converted \ --html-extension -o /home/me/weeklog \ http://www.gnu.org/ @end example Or, with less typing: @example wget -m -k -K -E http://www.gnu.org/ -o /home/me/weeklog @end example @end itemize @c man end @node Various @chapter Various @cindex various This chapter contains all the stuff that could not fit anywhere else. @menu * Proxies:: Support for proxy servers * Distribution:: Getting the latest version. * Mailing List:: Wget mailing list for announcements and discussion. * Reporting Bugs:: How and where to report bugs. * Portability:: The systems Wget works on. * Signals:: Signal-handling performed by Wget. @end menu @node Proxies @section Proxies @cindex proxies @dfn{Proxies} are special-purpose @sc{http} servers designed to transfer data from remote servers to local clients. One typical use of proxies is lightening network load for users behind a slow connection. This is achieved by channeling all @sc{http} and @sc{ftp} requests through the proxy which caches the transferred data. When a cached resource is requested again, proxy will return the data from cache. Another use for proxies is for companies that separate (for security reasons) their internal networks from the rest of Internet. In order to obtain information from the Web, their users connect and retrieve remote data using an authorized proxy. Wget supports proxies for both @sc{http} and @sc{ftp} retrievals. The standard way to specify proxy location, which Wget recognizes, is using the following environment variables: @table @code @item http_proxy This variable should contain the @sc{url} of the proxy for @sc{http} connections. @item ftp_proxy This variable should contain the @sc{url} of the proxy for @sc{ftp} connections. It is quite common that @sc{http_proxy} and @sc{ftp_proxy} are set to the same @sc{url}. @item no_proxy This variable should contain a comma-separated list of domain extensions proxy should @emph{not} be used for. For instance, if the value of @code{no_proxy} is @samp{.mit.edu}, proxy will not be used to retrieve documents from MIT. @end table In addition to the environment variables, proxy location and settings may be specified from within Wget itself. @table @samp @itemx --no-proxy @itemx proxy = on/off This option and the corresponding command may be used to suppress the use of proxy, even if the appropriate environment variables are set. @item http_proxy = @var{URL} @itemx ftp_proxy = @var{URL} @itemx no_proxy = @var{string} These startup file variables allow you to override the proxy settings specified by the environment. @end table Some proxy servers require authorization to enable you to use them. The authorization consists of @dfn{username} and @dfn{password}, which must be sent by Wget. As with @sc{http} authorization, several authentication schemes exist. For proxy authorization only the @code{Basic} authentication scheme is currently implemented. You may specify your username and password either through the proxy @sc{url} or through the command-line options. Assuming that the company's proxy is located at @samp{proxy.company.com} at port 8001, a proxy @sc{url} location containing authorization data might look like this: @example http://hniksic:mypassword@@proxy.company.com:8001/ @end example Alternatively, you may use the @samp{proxy-user} and @samp{proxy-password} options, and the equivalent @file{.wgetrc} settings @code{proxy_user} and @code{proxy_password} to set the proxy username and password. @node Distribution @section Distribution @cindex latest version Like all GNU utilities, the latest version of Wget can be found at the master GNU archive site ftp.gnu.org, and its mirrors. For example, Wget @value{VERSION} can be found at @url{ftp://ftp.gnu.org/pub/gnu/wget/wget-@value{VERSION}.tar.gz} @node Mailing List @section Mailing List @cindex mailing list @cindex list There are several Wget-related mailing lists, all hosted by SunSITE.dk. The general discussion list is at @email{wget@@sunsite.dk}. It is the preferred place for bug reports and suggestions, as well as for discussion of development. You are invited to subscribe. To subscribe, simply send mail to @email{wget-subscribe@@sunsite.dk} and follow the instructions. Unsubscribe by mailing to @email{wget-unsubscribe@@sunsite.dk}. The mailing list is archived at @url{http://www.mail-archive.com/wget%40sunsite.dk/} and at @url{http://news.gmane.org/gmane.comp.web.wget.general}. The second mailing list is at @email{wget-patches@@sunsite.dk}, and is used to submit patches for review by Wget developers. A ``patch'' is a textual representation of change to source code, readable by both humans and programs. The file @file{PATCHES} that comes with Wget covers the creation and submitting of patches in detail. Please don't send general suggestions or bug reports to @samp{wget-patches}; use it only for patch submissions. To subscribe, simply send mail to @email{wget-subscribe@@sunsite.dk} and follow the instructions. Unsubscribe by mailing to @email{wget-unsubscribe@@sunsite.dk}. The mailing list is archived at @url{http://news.gmane.org/gmane.comp.web.wget.patches}. @node Reporting Bugs @section Reporting Bugs @cindex bugs @cindex reporting bugs @cindex bug reports @c man begin BUGS You are welcome to send bug reports about GNU Wget to @email{bug-wget@@gnu.org}. Before actually submitting a bug report, please try to follow a few simple guidelines. @enumerate @item Please try to ascertain that the behavior you see really is a bug. If Wget crashes, it's a bug. If Wget does not behave as documented, it's a bug. If things work strange, but you are not sure about the way they are supposed to work, it might well be a bug. @item Try to repeat the bug in as simple circumstances as possible. E.g. if Wget crashes while downloading @samp{wget -rl0 -kKE -t5 -Y0 http://yoyodyne.com -o /tmp/log}, you should try to see if the crash is repeatable, and if will occur with a simpler set of options. You might even try to start the download at the page where the crash occurred to see if that page somehow triggered the crash. Also, while I will probably be interested to know the contents of your @file{.wgetrc} file, just dumping it into the debug message is probably a bad idea. Instead, you should first try to see if the bug repeats with @file{.wgetrc} moved out of the way. Only if it turns out that @file{.wgetrc} settings affect the bug, mail me the relevant parts of the file. @item Please start Wget with @samp{-d} option and send us the resulting output (or relevant parts thereof). If Wget was compiled without debug support, recompile it---it is @emph{much} easier to trace bugs with debug support on. Note: please make sure to remove any potentially sensitive information from the debug log before sending it to the bug address. The @code{-d} won't go out of its way to collect sensitive information, but the log @emph{will} contain a fairly complete transcript of Wget's communication with the server, which may include passwords and pieces of downloaded data. Since the bug address is publically archived, you may assume that all bug reports are visible to the public. @item If Wget has crashed, try to run it in a debugger, e.g. @code{gdb `which wget` core} and type @code{where} to get the backtrace. This may not work if the system administrator has disabled core files, but it is safe to try. @end enumerate @c man end @node Portability @section Portability @cindex portability @cindex operating systems Like all GNU software, Wget works on the GNU system. However, since it uses GNU Autoconf for building and configuring, and mostly avoids using ``special'' features of any particular Unix, it should compile (and work) on all common Unix flavors. Various Wget versions have been compiled and tested under many kinds of Unix systems, including GNU/Linux, Solaris, SunOS 4.x, OSF (aka Digital Unix or Tru64), Ultrix, *BSD, IRIX, AIX, and others. Some of those systems are no longer in widespread use and may not be able to support recent versions of Wget. If Wget fails to compile on your system, we would like to know about it. Thanks to kind contributors, this version of Wget compiles and works on 32-bit Microsoft Windows platforms. It has been compiled successfully using MS Visual C++ 6.0, Watcom, Borland C, and GCC compilers. Naturally, it is crippled of some features available on Unix, but it should work as a substitute for people stuck with Windows. Note that Windows-specific portions of Wget are not guaranteed to be supported in the future, although this has been the case in practice for many years now. All questions and problems in Windows usage should be reported to Wget mailing list at @email{wget@@sunsite.dk} where the volunteers who maintain the Windows-related features might look at them. @node Signals @section Signals @cindex signal handling @cindex hangup Since the purpose of Wget is background work, it catches the hangup signal (@code{SIGHUP}) and ignores it. If the output was on standard output, it will be redirected to a file named @file{wget-log}. Otherwise, @code{SIGHUP} is ignored. This is convenient when you wish to redirect the output of Wget after having started it. @example $ wget http://www.gnus.org/dist/gnus.tar.gz & ... $ kill -HUP %% SIGHUP received, redirecting output to `wget-log'. @end example Other than that, Wget will not try to interfere with signals in any way. @kbd{C-c}, @code{kill -TERM} and @code{kill -KILL} should kill it alike. @node Appendices @chapter Appendices This chapter contains some references I consider useful. @menu * Robot Exclusion:: Wget's support for RES. * Security Considerations:: Security with Wget. * Contributors:: People who helped. @end menu @node Robot Exclusion @section Robot Exclusion @cindex robot exclusion @cindex robots.txt @cindex server maintenance It is extremely easy to make Wget wander aimlessly around a web site, sucking all the available data in progress. @samp{wget -r @var{site}}, and you're set. Great? Not for the server admin. As long as Wget is only retrieving static pages, and doing it at a reasonable rate (see the @samp{--wait} option), there's not much of a problem. The trouble is that Wget can't tell the difference between the smallest static page and the most demanding CGI. A site I know has a section handled by a CGI Perl script that converts Info files to @sc{html} on the fly. The script is slow, but works well enough for human users viewing an occasional Info file. However, when someone's recursive Wget download stumbles upon the index page that links to all the Info files through the script, the system is brought to its knees without providing anything useful to the user (This task of converting Info files could be done locally and access to Info documentation for all installed GNU software on a system is available from the @code{info} command). To avoid this kind of accident, as well as to preserve privacy for documents that need to be protected from well-behaved robots, the concept of @dfn{robot exclusion} was invented. The idea is that the server administrators and document authors can specify which portions of the site they wish to protect from robots and those they will permit access. The most popular mechanism, and the @i{de facto} standard supported by all the major robots, is the ``Robots Exclusion Standard'' (RES) written by Martijn Koster et al. in 1994. It specifies the format of a text file containing directives that instruct the robots which URL paths to avoid. To be found by the robots, the specifications must be placed in @file{/robots.txt} in the server root, which the robots are expected to download and parse. Although Wget is not a web robot in the strictest sense of the word, it can downloads large parts of the site without the user's intervention to download an individual page. Because of that, Wget honors RES when downloading recursively. For instance, when you issue: @example wget -r http://www.server.com/ @end example First the index of @samp{www.server.com} will be downloaded. If Wget finds that it wants to download more documents from that server, it will request @samp{http://www.server.com/robots.txt} and, if found, use it for further downloads. @file{robots.txt} is loaded only once per each server. Until version 1.8, Wget supported the first version of the standard, written by Martijn Koster in 1994 and available at @url{http://www.robotstxt.org/wc/norobots.html}. As of version 1.8, Wget has supported the additional directives specified in the internet draft @samp{} titled ``A Method for Web Robots Control''. The draft, which has as far as I know never made to an @sc{rfc}, is available at @url{http://www.robotstxt.org/wc/norobots-rfc.txt}. This manual no longer includes the text of the Robot Exclusion Standard. The second, less known mechanism, enables the author of an individual document to specify whether they want the links from the file to be followed by a robot. This is achieved using the @code{META} tag, like this: @example @end example This is explained in some detail at @url{http://www.robotstxt.org/wc/meta-user.html}. Wget supports this method of robot exclusion in addition to the usual @file{/robots.txt} exclusion. If you know what you are doing and really really wish to turn off the robot exclusion, set the @code{robots} variable to @samp{off} in your @file{.wgetrc}. You can achieve the same effect from the command line using the @code{-e} switch, e.g. @samp{wget -e robots=off @var{url}...}. @node Security Considerations @section Security Considerations @cindex security When using Wget, you must be aware that it sends unencrypted passwords through the network, which may present a security problem. Here are the main issues, and some solutions. @enumerate @item The passwords on the command line are visible using @code{ps}. The best way around it is to use @code{wget -i -} and feed the @sc{url}s to Wget's standard input, each on a separate line, terminated by @kbd{C-d}. Another workaround is to use @file{.netrc} to store passwords; however, storing unencrypted passwords is also considered a security risk. @item Using the insecure @dfn{basic} authentication scheme, unencrypted passwords are transmitted through the network routers and gateways. @item The @sc{ftp} passwords are also in no way encrypted. There is no good solution for this at the moment. @item Although the ``normal'' output of Wget tries to hide the passwords, debugging logs show them, in all forms. This problem is avoided by being careful when you send debug logs (yes, even when you send them to me). @end enumerate @node Contributors @section Contributors @cindex contributors @iftex GNU Wget was written by Hrvoje Nik@v{s}i@'{c} @email{hniksic@@xemacs.org}. @end iftex @ifnottex GNU Wget was written by Hrvoje Niksic @email{hniksic@@xemacs.org}. @end ifnottex However, its development could never have gone as far as it has, were it not for the help of many people, either with bug reports, feature proposals, patches, or letters saying ``Thanks!''. Special thanks goes to the following people (no particular order): @itemize @bullet @item Mauro Tortonesi---contributed high-quality IPv6 code and many other fixes. @item Dan Harkless---contributed a lot of code and documentation of extremely high quality, as well as the @code{--page-requisites} and related options. He was the principal maintainer for some time and released Wget 1.6. @item Ian Abbott---contributed bug fixes, Windows-related fixes, and provided a prototype implementation of the breadth-first recursive download. Co-maintained Wget during the 1.8 release cycle. @item The dotsrc.org crew, in particular Karsten Thygesen---donated system resources such as the mailing list, web space, @sc{ftp} space, and version control repositories, along with a lot of time to make these actually work. Christian Reiniger was of invaluable help with setting up Subversion. @item Heiko Herold---provided high-quality Windows builds and contributed bug and build reports for many years. @item Shawn McHorse---bug reports and patches. @item Kaveh R. Ghazi---on-the-fly @code{ansi2knr}-ization. Lots of portability fixes. @item Gordon Matzigkeit---@file{.netrc} support. @item @iftex Zlatko @v{C}alu@v{s}i@'{c}, Tomislav Vujec and Dra@v{z}en Ka@v{c}ar---feature suggestions and ``philosophical'' discussions. @end iftex @ifnottex Zlatko Calusic, Tomislav Vujec and Drazen Kacar---feature suggestions and ``philosophical'' discussions. @end ifnottex @item Darko Budor---initial port to Windows. @item Antonio Rosella---help and suggestions, plus the initial Italian translation. @item @iftex Tomislav Petrovi@'{c}, Mario Miko@v{c}evi@'{c}---many bug reports and suggestions. @end iftex @ifnottex Tomislav Petrovic, Mario Mikocevic---many bug reports and suggestions. @end ifnottex @item @iftex Fran@,{c}ois Pinard---many thorough bug reports and discussions. @end iftex @ifnottex Francois Pinard---many thorough bug reports and discussions. @end ifnottex @item Karl Eichwalder---lots of help with internationalization, Makefile layout and many other things. @item Junio Hamano---donated support for Opie and @sc{http} @code{Digest} authentication. @item People who provided donations for development---including Brian Gough. @end itemize The following people have provided patches, bug/build reports, useful suggestions, beta testing services, fan mail and all the other things that make maintenance so much fun: Tim Adam, Adrian Aichner, Martin Baehr, Dieter Baron, Roger Beeman, Dan Berger, T. Bharath, Christian Biere, Paul Bludov, Daniel Bodea, Mark Boyns, John Burden, Wanderlei Cavassin, Gilles Cedoc, Tim Charron, Noel Cragg, @iftex Kristijan @v{C}onka@v{s}, @end iftex @ifnottex Kristijan Conkas, @end ifnottex John Daily, Andreas Damm, Ahmon Dancy, Andrew Davison, Bertrand Demiddelaer, Andrew Deryabin, Ulrich Drepper, Marc Duponcheel, @iftex Damir D@v{z}eko, @end iftex @ifnottex Damir Dzeko, @end ifnottex Alan Eldridge, Hans-Andreas Engel, @iftex Aleksandar Erkalovi@'{c}, @end iftex @ifnottex Aleksandar Erkalovic, @end ifnottex Andy Eskilsson, Christian Fraenkel, David Fritz, Charles C. Fu, FUJISHIMA Satsuki, Masashi Fujita, Howard Gayle, Marcel Gerrits, Lemble Gregory, Hans Grobler, Mathieu Guillaume, Aaron Hawley, Jochen Hein, Karl Heuer, HIROSE Masaaki, Ulf Harnhammar, Gregor Hoffleit, Erik Magnus Hulthen, Richard Huveneers, Jonas Jensen, Larry Jones, Simon Josefsson, @iftex Mario Juri@'{c}, @end iftex @ifnottex Mario Juric, @end ifnottex @iftex Hack Kampbj@o rn, @end iftex @ifnottex Hack Kampbjorn, @end ifnottex Const Kaplinsky, @iftex Goran Kezunovi@'{c}, @end iftex @ifnottex Goran Kezunovic, @end ifnottex Igor Khristophorov, Robert Kleine, KOJIMA Haime, Fila Kolodny, Alexander Kourakos, Martin Kraemer, Sami Krank, @tex $\Sigma\acute{\iota}\mu o\varsigma\; \Xi\varepsilon\nu\iota\tau\acute{\epsilon}\lambda\lambda\eta\varsigma$ (Simos KSenitellis), @end tex @ifnottex Simos KSenitellis, @end ifnottex Christian Lackas, Hrvoje Lacko, Daniel S. Lewart, @iftex Nicol@'{a}s Lichtmeier, @end iftex @ifnottex Nicolas Lichtmeier, @end ifnottex Dave Love, Alexander V. Lukyanov, @iftex Thomas Lu@ss{}nig, @end iftex @ifnottex Thomas Lussnig, @end ifnottex Andre Majorel, Aurelien Marchand, Matthew J. Mellon, Jordan Mendelson, Lin Zhe Min, Jan Minar, Tim Mooney, Keith Moore, Adam D. Moss, Simon Munton, Charlie Negyesi, R. K. Owen, Leonid Petrov, Simone Piunno, Andrew Pollock, Steve Pothier, @iftex Jan P@v{r}ikryl, @end iftex @ifnottex Jan Prikryl, @end ifnottex Marin Purgar, @iftex Csaba R@'{a}duly, @end iftex @ifnottex Csaba Raduly, @end ifnottex Keith Refson, Bill Richardson, Tyler Riddle, Tobias Ringstrom, @c Texinfo doesn't grok @'{@i}, so we have to use TeX itself. @tex Juan Jos\'{e} Rodr\'{\i}guez, @end tex @ifnottex Juan Jose Rodriguez, @end ifnottex Maciej W. Rozycki, Edward J. Sabol, Heinz Salzmann, Robert Schmidt, Nicolas Schodet, Andreas Schwab, Steven M. Schweda, Chris Seawood, Dennis Smit, Toomas Soome, Tage Stabell-Kulo, Philip Stadermann, Daniel Stenberg, Sven Sternberger, Markus Strasser, John Summerfield, Szakacsits Szabolcs, Mike Thomas, Philipp Thomas, Mauro Tortonesi, Dave Turner, Gisle Vanem, Russell Vincent, @iftex @v{Z}eljko Vrba, @end iftex @ifnottex Zeljko Vrba, @end ifnottex Charles G Waldman, Douglas E. Wegscheid, YAMAZAKI Makoto, Jasmin Zainul, @iftex Bojan @v{Z}drnja, @end iftex @ifnottex Bojan Zdrnja, @end ifnottex Kristijan Zimmer. Apologies to all who I accidentally left out, and many thanks to all the subscribers of the Wget mailing list. @node Copying @chapter Copying @cindex copying @cindex GPL @cindex GFDL @cindex free software GNU Wget is licensed under the GNU General Public License (GNU GPL), which makes it @dfn{free software}. Please note that ``free'' in ``free software'' refers to liberty, not price. As some people like to point out, it's the ``free'' of ``free speech'', not the ``free'' of ``free beer''. The exact and legally binding distribution terms are spelled out below. The GPL guarantees that you have the right (freedom) to run and change GNU Wget and distribute it to others, and even---if you want---charge money for doing any of those things. With these rights comes the obligation to distribute the source code along with the software and to grant your recipients the same rights and impose the same restrictions. This licensing model is also known as @dfn{open source} because it, among other things, makes sure that all recipients will receive the source code along with the program, and be able to improve it. The GNU project prefers the term ``free software'' for reasons outlined at @url{http://www.gnu.org/philosophy/free-software-for-freedom.html}. The exact license terms are defined by this paragraph and the GNU General Public License it refers to: @quotation GNU Wget is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. GNU Wget is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. A copy of the GNU General Public License is included as part of this manual; if you did not receive it, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. @end quotation In addition to this, this manual is free in the same sense: @quotation Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being ``GNU General Public License'' and ``GNU Free Documentation License'', with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. @end quotation @c #### Maybe we should wrap these licenses in ifinfo? Stallman says @c that the GFDL needs to be present in the manual, and to me it would @c suck to include the license for the manual and not the license for @c the program. The full texts of the GNU General Public License and of the GNU Free Documentation License are available below. @menu * GNU General Public License:: * GNU Free Documentation License:: @end menu @include gpl.texi @include fdl.texi @node Concept Index @unnumbered Concept Index @printindex cp @contents @bye