CODEWITHSUNDEEP
bashfor-loopwildcard
xoid
xoid

Reputation: 1134

"for" loop wildcard evaluated to variable if no such files present

$ for f in /etc/shell*; do echo $f; done
/etc/shells
$

good!

$ for f in /etc/no_such*; do echo $f; done
/etc/no_such*
$

BAD!

How can I reap off wildcard evaluation if no files present?

Upvotes: 4

Views: 409

Answers (1)

Tom Fenech
Tom Fenech

Reputation: 74685

There is a specific shell option to enable this behaviour with globs, called nullglob. To enable it, use shopt -s nullglob.

When this option is enabled, a pattern with no matches evaluates to nothing, rather than to itself.

This is non-standard feature provided by bash, so if you're using another shell or are looking for a more widely compatible option you can add a condition to the loop body:

for f in /etc/no_such*; do [ -e "$f" ] && echo "$f"; done

This will only echo if the file exists.

Upvotes: 6

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