Yeah, that's true. But we could turn it around and then it works: 

#!/usr/bin/perl -w

use strict;
use warnings;


my $SAMPLE = "Hello World\r\n";
my $MATCHALL = "ooreH\r\n";
my $SAMPLE_LENGTH = length($SAMPLE);

$SAMPLE =~ s/[\Q$MATCHALL\E]{1}//g;

if (length($SAMPLE) == $SAMPLE_LENGTH - length($MATCHALL))
{
  print "\nCONTAINS ALL THE CHARACTERS\n";
}
else
{
  print "\nDOES NOT CONTAIN ALL THE CHARACTERS\n";
}

exit;

[download]

In reply to Re^3: string containing characters by harangzsolt33
in thread string containing characters by IvanH

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