Here's a very simple example showing how to use grep to do what you want (although that may not be the best way!):

use strict; use warnings;
use feature qw/ say /;

my %hash_name = (
  "one" => 1,
  "two" => 2,
  "three" => 3,
  "four" => 4
);

while ( my $line = <DATA> ) {
    chomp $line;
    say "Line $. : $hash_name{$_}" for grep { $line =~ /$_/ } sort key
+s %hash_name;
}

__DATA__
This one has it.
This doesn't.
This one has two.
Nothing here.
Three times lucky.
Can we get a foursome for tennis?
Blerghh.
[download]

Output:

Line 1 : 1
Line 3 : 1
Line 3 : 2
Line 6 : 4
[download]

Hope this helps!