Re: [libvirt] [PATCH 0/4] generate SYNTAX section of "virsh help CMD" output

This started when I noticed that a lot of virsh help output was out of date. Dan Berrange suggested to generate the SYNTAX line automatically based on existing option descriptions, since they tell us what arguments/types each command accepts and can (usually) tell us when options or arguments are optional. Doing this exposed several inaccurate SYNTAX lines, as well as some inaccurate option descriptions. But since the option description structs are currently used only to generate the text of ./virsh help's OPTIONS section, it's not terribly important. Other than changes to help output, this change induces some minor user-visible changes: It is currently undocumented that virsh accepts "-h C1 C2 C3..." and treats it like "virsh help C1", ignoring C2 C3... This change disables that feature (to clean up a few interfaces and to make automatic help SYNTAX generation simpler) and makes virsh diagnose any unused arguments with --help (-h), so now, this command fails rather than trying to interpret "A" as a command: $ virsh -h -c test:///default A virsh: error: extra argument 'A'. See --help. To view the other changes induced by this patch, I've run the following commands: v='virsh -c test:///default' cmd=$(eval $v help|sed -n 's/^ \([^ ][^ ]*\) .*/\1/p') for i in $(echo $cmd); do diff -ubBw -L $i.orig -L $i.new <(eval $v help $i) <(eval ./$v help $i) done They use diff to compare e.g., the output of my just-built ./virsh and the installed-in-PATH "virsh" program. Note that there is currently no way via options to indicate that one of two or more options must be selected, so the automatically generated syntax string list both as independent options. Here are the induced help changes: [code diffs coming in separate messages]