How is -e $file true when $image is the empty string '' or even undef?

-e (or any of the other filetest functions documented here) accepts either a filehandle or a directory handle as its argument. When $image is empty or undefined, the assignment my $file = "$dir/$image"; initialises $file to just $dir/, which -e accepts as a directory handle — and since that directory exists, -e returns true.

(Note that if warnings are enabled, the concatenation of a string with undef will result in a warning like this:

Use of uninitialized value $image in concatenation (.) or string at -e
+ line...

[download]

which is a useful indicator that something is wrong.)

Your suggested fix — checking that $image has a true value — looks good to me. Another possibility is to confirm that $file is not a directory:

if (!-d $image && -e $image) {
    print "Yes image exists\n";
}
else {
    print "No image doesn't exist\n";
}

[download]

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: Check if file exists by Athanasius
in thread Check if file exists by Anonymous Monk

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