use DB_File; tie %password, 'DB_File', "./pw_aux", O_CREAT|O_RDWR, 0666 or die $!; open PASSWD, "<", "/etc/passwd" or die $!; make_index(\*PASSWD, \%password, sub { (split /:/, $_[0], 2)[0] }, ); print find(\*PASSWD, \%password, "mjd"); exit 0; use Fcntl ':seek'; sub make_index { my ($fh, $dbm, $key_function) = @_; seek $fh, 0, SEEK_SET; %$dbm = (); my $pos = 0; while (<$fh>) { chomp; my $key = $key_function->($_); $dbm->{$key} = $pos; $pos = tell $fh; } } sub find { my ($fh, $dbm, $key) = @_; my $offset = $dbm->{$key}; seek $fh, $offset, SEEK_SET; my $rec = <$fh>; return $rec; }