Test whether a glob has any matches in bash

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夕颜 2020-11-22 15:51

If I want to check for the existence of a single file, I can test for it using test -e filename or [ -e filename ].

Supposing I have a glob

19条回答
  •  一个人的身影
    2020-11-22 16:43

    The nullglob shell option is indeed a bashism.

    To avoid the need for a tedious save and restore of the nullglob state, I'd only set it inside the subshell that expands the glob:

    if test -n "$(shopt -s nullglob; echo glob*)"
    then
        echo found
    else
        echo not found
    fi
    

    For better portability and more flexible globbing, use find:

    if test -n "$(find . -maxdepth 1 -name 'glob*' -print -quit)"
    then
        echo found
    else
        echo not found
    fi
    

    Explicit -print -quit actions are used for find instead of the default implicit -print action so that find will quit as soon as it finds the first file matching the search criteria. Where lots of files match, this should run much faster than echo glob* or ls glob* and it also avoids the possibility of overstuffing the expanded command line (some shells have a 4K length limit).

    If find feels like overkill and the number of files likely to match is small, use stat:

    if stat -t glob* >/dev/null 2>&1
    then
        echo found
    else
        echo not found
    fi
    

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