moparisthebest/wget
1
0
Fork 0
mirror of https://github.com/moparisthebest/wget synced 2024-07-03 16:38:41 -04:00
Code Issues Releases Wiki Activity

[svn] wget.texi (Download Options): Further improvement to --continue documentation --

Browse Source 
explain interaction with -r and -N, mention usefulness for downloading new
sections of appended-to files, etc.
This commit is contained in:
dan 2001-02-19 15:22:48 -08:00
parent 4fc318600e
commit c9471c3b38
2 changed files with 38 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
doc/ChangeLog
View File

@ -1,3 +1,9 @@
2001-02-19 Dan Harkless <wget@harkless.org>
* wget.texi (Download Options): Further improvement to --continue
documentation -- explain interaction with -r and -N, mention
usefulness for downloading new sections of appended-to files, etc.
2001-01-06 Jan Prikryl <prikryl@cg.tuwien.ac.at>
* wget.texi (Reporting Bugs): Deleted the setence about Cc-ing the
@ -18,8 +24,8 @@
2001-01-09 Dan Harkless <wget@harkless.org>
* wget.texi: Did a bunch of clarification and correction to the
description of --continue.
* wget.texi (Download Options): Did a bunch of clarification and
correction to the description of --continue.
2001-01-06 Dan Harkless <wget@harkless.org>

39
doc/wget.texi
View File

@ -547,6 +547,7 @@ Note that when @samp{-nc} is specified, files with the suffixes
and parsed as if they had been retrieved from the Web.
@cindex continue retrieval
@cindex incomplete downloads
@cindex resume download
@item -c
@itemx --continue
@ -573,17 +574,37 @@ 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.
Note that @samp{-c} only works with @sc{ftp} servers and with @sc{http}
servers that support the @code{Range} header. Also note that Wget has
no way of verifying that the local file really is a valid prefix of the
remote file. If you use a lame @sc{http} proxy that inserts a ``transfer
interrupted'' string, you'll get a corrupted file. In the future a
If you use @samp{-c} on a file which is now smaller on the server than
locally (presumably because it was changed on the server since your last
download attempt), the file will be re-downloaded from scratch.
Unfortunately this also happens if the local file is the same length as
the server file---this will be fixed in a future version of Wget, but in
the meantime you can use @samp{--timestamping} to prevent this on files
for which the server gives timestamps (e.g. static files but not CGI
output or directory listings).
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(server) - 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.
Currently, if you use @samp{-c} on a @file{file} that's already
completely downloaded, it will be re-downloaded from scratch (to the
same name, not to @file{file.1}). This will be fixed in a future
version of Wget.
Note that @samp{-c} only works with @sc{ftp} servers and with @sc{http}
servers that support the @code{Range} header.
@cindex dot style
@cindex retrieval tracing style