How do I handle null_glob results in fish?

问题

I have a fish function that contains the following rm statement:

rm ~/path/to/dir/*.log

This statement works fine if there are *.log files in that path, but fails when there are no *.log files. The error is:

~/.config/fish/functions/myfunc.fish (line 5): No matches for wildcard '~/path/to/dir/*.log'. See `help expand`.
    rm ~/path/to/dir/*.log
       ^
in function 'myfunc'
        called on standard input

ZSH has what are called Glob Qualifiers. One of them, N, handles setting the NULL_GLOB option for the current pattern, which essentially does what I want:

If a pattern for filename generation has no matches, delete the pattern from the argument list instead of reporting an error.

I understand that fish doesn't have ZSH-style glob qualifiers, but I am unclear how to handle this scenario in my fish functions. Should I be looping through an array? It seems really verbose. Or is there a more fishy way of handling this scenario?

# A one-liner in ZSH becomes this in fish?
set -l arr ~/path/to/dir/*.log
for f in $arr
    rm $f
end

回答1:

fish does not support rich globs, but count, set, and for are special in that they nullglob. So you could write:

set files ~/path/to/dir/*.log; rm -f $files

(The -f is required because rm complains if you pass it zero arguments.)

count could also work:

count ~/path/to/dir/*.log >/dev/null && rm ~/path/to/dir/*.log

For completeness, a loop:

for file in ~/path/to/dir/*.log ; rm $file; end

来源：https://stackoverflow.com/questions/58720232/how-do-i-handle-null-glob-results-in-fish

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