We forgot to make sure that there is no more than one pattern
parameter. Also when looking for files in a directory called
'--others', it passed that path limiter without preceding the
end-of-options marker '--' to underlying git-ls-files, which
misunderstood it as one of its options instead.
$ git grep --others -e Meta/Make Meta
$ git grep -o -e Meta/Make Meta
$ git grep -o Meta/Make Meta
look for a string "Meta/Make" from untracked files in Meta/
directory.
$ git grep Meta/Make --others
looks for the same string from tracked files in ./--others
directory.
On the other hand,
$ git grep -e Meta/Make --others
does not have a freestanding pattern, so everybody is parameter
and there is no path specifier. It looks for the string in all
the untracked files without any path limiter.
[jc: updated with usability enhancements and documentation
cleanups from Sean.]
Signed-off-by: Junio C Hamano <junkio@cox.net>