[linux-help] Re: Quick BASH/Perl Question

[Tom Hull <thull@xxxxxxxxxxx>]

Curtis Hawthorne wrote:
> 
> First, in BASH, how do I test for the presence of any
> .log (*.log) file in a directory?  If I do "test -a
> *.log" it says there's too many arguments.

One way, the exit status of ls(1) is 0 if the argument files exist, or
1 if one or more files do not exist:

    if ls *.log >/dev/null 2>&1; then
        echo "got some .log files"
    else
        echo "ain't got no .log files"
    fi

You can pipe ls | wc -l to get a file count, but beware of the idiot
whitespace that wc(1) adds:

    nfiles=`ls -d *.log 2>/dev/null | wc -l | tr -d ' '`
    if [ "$nfiles" != 0 ]; then
        echo "got $nfiles .log files"
    else
        echo "ain't got no .log files"
    fi

You could replace the wc/tr with the non-obvious:

    nfiles=`ls -d *.log 2>/dev/null | awk 'END{print NR}'`

You could also do something like:

    set `ls *.md 2>/dev/null`
    nfiles=$#

You could also set and take the dimension of a bash array, but offhand
I don't know how to do that.

-- 
/*
 *  Tom Hull * thull at kscable.com * http://www.ocston.org/~thull/
 */

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