Try this:

#!/usr/bin/env perl                                                   
+                         

use strict;
use warnings;

my $char = shift || die $!;
my $file = $0;

open( my $fh, "<", $file ) || die $!;

while (<$fh>) {
    print if /^o/; # your part goes here
}

close $fh;

__END__
[download]

Please see also strict, warnings, my, shift, die, while, open, print, if, close, perlretut as well as TMTOWTDI.

For the rest: RTFM ;-)

Update: Immediate feedback is a good thing. But please note: I really didn't want to be harsh or impolite. And i marked the dubious hint as a joke.

Regards, Karl