CODEWITHSUNDEEP
perl
theillien
theillien

Reputation: 1390

Perl: File test for zero size (-z) not executing as expected

I've written a script which scans a server for world-writable files. In the middle of the script is a bit of code which tests for the existence, non-existence, or zero size of a file.

# Read in the list of excluded files and create a regex from them
if (-e $exclude) {
  $regExcld = do {
    open XCLD, "<${exclude}" or die "Cannot open ${exclude}, $!\n";
    my @ignore = <XCLD>;
    chomp @ignore;
    local $" = '|';
    qr/@ignore/;
  };

} elsif ((! -e $exclude) || (-z $exclude)) {
  $errHeader = <<HEADER;
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                                                  !!
!! /usr/local/etc/world_writable_excludes.txt is    !!
!! is missing or empty. This report includes        !!
!! every world-writable file including those which  !!
!! are expected and should be excluded.             !!
!!                                                  !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


HEADER

}

If I remove the file being tested the $errHeader variable is set appropriately per the does-not-exist test and, further down the script, is properly written to the output file. However, if I create the file and leave it empty the $errHeader variable is not set properly.

I've reordered the tests putting the zero-size test above the does-not-exist test with the same result.

In another, simple test it works:

#!/usr/bin/perl

my $test;

if (-z "/usr/local/etc/world_writable_excludes.txt") {
  $test = "Zero Size";

}

if ($test) {
  print $test . "\n";

}

Upvotes: 0

Views: 610

Answers (1)

Hameed
Hameed

Reputation: 2277

The problem is with -e being your first condition. It is true even if your file has size 0. Try !-e first, then -z and then -e.

Upvotes: 2

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