use strict;
use warnings;

my %hash;

while(<DATA>){
	my ($key, $value) = split(/\s+/, $_);
    $hash{$key} = $value;
}

foreach(keys %hash){
    if ($_ =~ /this|is|a|test/){
	    print "found string \"$_\" and its value is \"$hash{$_}\"\n";
	}
}

__DATA__
this 1
is 2
a 3
test 4