You are recreating the functionality of grep.

Where you are using grep, that should be just a regexp or (even better) index. But back to the point, grep works on a list and returns a list of matches

#!/usr/bin/perl -w

use strict;


my @lines = (
              'this is line one',
              'this is line TWO',
              'this is line three',
              'this is line four perl',
              'this is line fiveperl',
              'perl'
              );

my @search = grep { index($_,'perl')+1 } @lines;
# my @search = grep {/perl/} @lines;
#
# if you don't want line five use /\bperl\b/;

print "TRUE\n" if (@search);

foreach (@search) {
    print "$_\n";
}
[download]

If you do use a $var to populate your regexp please use quotemeta

As for your other question 'if (@array)' will return true if there are any elements in the array (even if the only element is 0 or undef)

UPDATE: BTW here is the benchmark on the re vs. index solution

Benchmark: timing 100000 iterations of index, re...
     index:  4 wallclock secs ( 3.54 usr +  0.00 sys =  3.54 CPU) @ 28
+248.59/s (n=100000)
        re:  7 wallclock secs ( 6.98 usr +  0.00 sys =  6.98 CPU) @ 14
+326.65/s (n=100000)
[download]

grep

Mynd you, mønk bites Kan be pretti nasti...