use strict;
use warnings;

my @array1 = qw (fil_  t_xt _erl);
my @array2 = qw (Merlin file text fils perl filled);

for my $stem (@array1) {
	my $re = $stem;
	$re =~ s/_/.+/;
	/\b$re\b/ and print "$stem: $_\n" for @array2;
}

##</code><code>##

fil_: file
fil_: fils
fil_: filled
t_xt: text
_erl: perl

##</code><code>##

use strict;
use warnings;

my @array1 = qw (fil_  t_xt _erl);
my @array2 = qw (Merlin file text fils perl filled);

my $words = join ' ', @array2;

for my $stem (@array1) {
	my $re = $stem;
	$re =~ s/_/./;
	print "$stem: $1\n" while $words =~ /\b($re)\b/g;
}

##</code><code>##

fil_: file
fil_: fils
t_xt: text
_erl: perl