my $file = '/home/bob/db.txt';
open my $fh, $file or die "$file: $!";

my $pass;

while (<$fh>) {
	chomp;
	my @fields = split /\s+/;
	if ($fields[0] eq 'user@example.com') {
		$pass = $fields[1];
		last;
	}
}
close $fh;