It sounds like you want to stop reading the file once you have found what you are looking for. If you read the file in a while loop you can break out of the loop with last. Like this

while (my $line = <$inputFH> )
{
    next unless $line =~ m{some pattern};

    # Process wanted line here ...

    last;  # Break out of while loop
}
[download]

I hope this helps you.

Cheers,

JohnGG