As per @horazont's feedback:
> You do not need () around the command in an if. I think that causes a subshell to spawn, the effects of which I'm not certain about.
Further Googling suggests that the exit status of a pipeline is that of the most recently executed foreground pipeline, meaning that the exit code can be used directly in conditional statements.
As per @horazont's feedback: `-u` shouts at you if you use an undefined variable (very useful to catch typos)
and `-o pipefail` improves error handling by also failing if any of the commands in a pipe fail.
This adds a simple bash script that checks if a provided file (filename to be provided as first argument) conforms to XEP-0001.
Expected to be executed from the directory that holds all xep XML files.
Requires one argument: the file name of the xep to be validated, eg:
$ tools/validate-xep0001-conformance.sh xep-0010.xml
exit status will be non-zero upon validation failure.
requires: bash, xmllint
