We have an Application called 'Tripwire' to monitor Security Compliance & Change. It was set up by another Deptmt. It is based on RegEx's, and my job is to ensure the RegEx's that are in it are working correctly. I've made progress, but have run into an issue I could use help with.

I have a script feed a RegEx from the command line which works.

My test passwd file (To test only root has UID=0)

$ cat passwd
root:x:0:0:ifeuu1 root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
noncom:x:0:0:cause RegEx Fail:/noncom:/bin/bash
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

[download]

The Script

#!/usr/bin/perl
# perl-grep4.pl

my $pattern = shift @ARGV;

my $regex = eval { qr/$pattern/ };
die "Check your pattern! $@" if $@;

while( <> )
    {
    if( m/$regex/ )
        {

        print "$_";

        print "\t\t\$&: ",
            substr( $_, $-[0], $+[0] - $-[0] ),
            "\n";

        foreach my $i ( 1 .. $#- )
            {
            print "\t\t\$$i: ",
                substr( $_, $-[$i], $+[$i] - $-[$i] ),
                "\n";
            }
        }
    }

[download]

Usage & Output

$ Test5.pl '(?<!\broot:)x:0:' passwd
noncom:x:0:0:cause RegEx Fail:/noncom:/bin/bash
                $&: x:0:

[download]

However, trying to get a script which is feed the RegEx from a file is failing

My RegEx-File

PW:root:passwd:(?<!\broot:)x:0:

[download]

The script

#!/usr/bin/perl
#use strict;
#use warnings;
use Text::ParseWords;
my ($RECORD, @FIELDS, $RE);
my $DFile="/home/infosec/data/RegEx";
open (DATA, "<$DFile") || die ("Cannot open DATA file \n");
my @LINES=<DATA>;
my $tLINES=@LINES;
foreach $RECORD (@LINES[0..$tLINES-1]) {
  @FIELDS=split(/:/, "$RECORD");
  my $TNAME=$FIELDS[0];
  my $TVALU=$FIELDS[1];
  my $TFILE=$FIELDS[2];
  my $REGEX=$FIELDS[3];
  chomp($REGEX);
  my $regex = eval { qr/$REGEX/ };
  print "$regex \n";
  open (TFILE, "<$TFILE") || die ("Cannot open Test file \n");
  while (<TFILE>)
    {
    if( m/$regex/ )
        {

        print "$_";

        print "\t\t\$&: ",
            substr( $_, $-[0], $+[0] - $-[0] ),
            "\n";

        foreach my $i ( 1 .. $#- )
            {
            print "\t\t\$$i: ",
                substr( $_, $-[$i], $+[$i] - $-[$i] ),
                "\n";
            }
        }
    }
  print "\n";
}
print "\n";

[download]

The output

$ Test6.pl

root:x:0:0:ifeuu1 root:/root:/bin/bash
                $&:
bin:x:1:1:bin:/bin:/sbin/nologin
                $&:
noncom:x:0:0:cause RegEx Fail:/noncom:/bin/bash
                $&:
daemon:x:2:2:daemon:/sbin:/sbin/nologin
                $&:
adm:x:3:4:adm:/var/adm:/sbin/nologin
                $&:
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
                $&:
sync:x:5:0:sync:/sbin:/bin/sync
                $&:
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
                $&:

[download]

This matches all lines instead of only the third, and I had trouble getting strict & warning to run clean. Could anyone help?

In reply to Test RegEx by Saved

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