Another way of doing this is to store a reference to your regex using qr(). For example,

#!/usr/bin/perl -w

use strict;

my $re = qr/hello/;

my $string1 = "hello";
my $string2 = "good bye";

if($string1 =~ $re){
    print "Match $string1\n";
}

if($string2 =~ $re){
    print "Match $string2\n";
}
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