~/perl/monks$ cat foo.txt
fish $1
~/perl/monks$

##</code><code>##

#!/usr/bin/perl 

open FOO, "<foo.txt";
$foo_from_file = <FOO>;

foo("This is test 1\n", qr/test (.*)/, $foo_from_file);

sub foo { (my $text = $_[0]) =~ s/$_[1]/interpolate($_[2],$1)/e;
          print $text; }

sub interpolate { my ($str,@vars) = @_;
                  $str =~ s/\$(\d+)/$vars[$1-1]/g;
                  $str }