No, I believe the "=~" is used in regex there, from my minimal understanding $test is the string that contains the regex. I am still trying to understand the how on the rest of the script, though.

Update: After some testing, I used a much simpler version to get to this.

 #!/usr/bin/perl -w 
use strict;

my $string='ABCD';
my $string1='DCBA';
my $test='.*?AB';

print "Matched in $string" if $string =~ $test;      # Prints Match.
print "Matched in $string1" if $string1 =~ $test;     # Does not print
+ Match.
[download]

So $test does contain the regex '.*?AB' or '.*?BA'. If I am not correct here, please let me know.

Update: Adjusted code to differentiate the output.