tail -f should send it's output to your perl script.

For example:

tail -f file.txt | script.pl

using the script.pl:

#!/usr/bin/perl 
use strict;

while (<STDIN>)
    {
        print STDERR "Received from tail -f:\t$_";
    }
[download]

does print to STDERR while tail -f is running. And if 'file.txt' is updated while tail -f is still running, the output is updated.

Do you really need to follow the log file continuously, or do you just want to create reports intermittently or on demand?

Maybe there's an issue in your perl script?

-Michael