Is this a text file, or a binary one (e.g. $FWDIR/log/fw.log is a binary file). Is it being written by the system or by FireWall-1, or by a script you wrote? I only ask because FireWall-1 has a command-line interface to its binary log format that may do what you want, and is scriptable.

If possible, the best way to deal with files like this is to not even bother reading them - but by sending the data from the generating process in realtime over a network socket, much as remote syslog does. That way, you don't have to worry about the file contents.

If the above is not an option, you could try File::Tail. Nokia's "unsupported" perl package installs in /opt, which *is* mounted read/write (unlike the root partition) so you should be able to make it work by installing it in one of the @INC directories, which are all under /opt/perl/lib/perl5.

Doug