Ignore "no matches" from zsh when using brace expansion with glob *.{a,b,}test

Question

I would like to list all of the files in a folder called foldername that have the extension test, atest or btest.

My immediate thought was to run ls ./foldername/*.{a,b,}test

This works fine unless there is nothing with the extension atest, in which case I get the error zsh: no matches found: ./foldername/*.atest.

Is there any way I can simply ignore this error and print the files that do exist?

I need this to work in both zsh and Bash.

Solution 1

It may be best to do this with find:

find ./foldername -maxdepth 1 -name '*.atest' -o -name '*.btest' -o -name '*.test'

Solution 2

In

ls -d ./foldername/*.{a,b,}test

{a,b,...} is not a glob operator, that's brace expansion, that's first expanded to:

ls -d ./foldername/*.atest ./foldername/*.btest ./foldername/*.test

And each glob expanded individually, and if any glob doesn't match, the command is cancelled as you'd expect in zsh (or fish; in bash, you need the failglob option to get a similar behaviour).

Here, you'd want to use a single glob that matches all those files, and only cancel the command if that one glob didn't match any file:

ls -d ./foldername/*.(a|b|)test

You don't want to use nullglob, as if none of the globs matched, it would run ls without arguments, so list the current directory. cshnullglob is better in that regard as it removes non-matching globs but still cancels the command if all the globs fail to match.

You wouldn't want to use nonomatch, as that would give you the broken behaviour of bash which would be a shame.

For a glob alternative that works in both zsh and bash, you could use the ksh globs (set -o kshglob in zsh and shopt -s extglob in bash).

Then, you'd do:

ls -d ./foldername/*.@(a|b|)test

or:

ls -d ./foldername/*.?([ab])test

Add the failglob option in bash to avoid the glob being passed literally to ls when it doesn't match.

See Why is nullglob not default? for more information.

Comments

[Pankaj Goyal]

Redirect standard error to /dev/null?

[Jeff Schaller]

I'm not sure why it's a requirement of the OP, but is there an extglob that works for this in both bash and zsh? I had to use ?(...) or +(...) for bash.

[Jeff Schaller]

perhaps with a -maxdepth 1, to closer emulate the ls behavior

[Stéphane Chazelas]

@JeffSchaller, note that -maxdepth is a GNU extension. Note 3 other differences with globs: find would include hidden files, not sort the list and fail to match file names that contain bytes not forming valid characters (like a $'St\xe9phane.atest' in a UTF-8 locale)

[Stéphane Chazelas]

@JeffSchaller, see edit

[Stéphane Chazelas]

No, it wouldn't work in zsh where this question is about as you'd only be redirecting ls' stderr, and ls is not even run here in zsh if any of those globs fail.