How do I do a "tail -f" in perl?

       First try

           seek(GWFILE, 0, 1);

       The statement "seek(GWFILE, 0, 1)" doesn't change the current position, but it does clear the end-of-
       file condition on the handle, so that the next <GWFILE> makes Perl try again to read something.

       If that doesn't work (it relies on features of your stdio implementation), then you need something
       more like this:

               for (;;) {
                 for ($curpos = tell(GWFILE); <GWFILE>; $curpos = tell(GWFILE)) {
                   # search for some stuff and put it into files
                 }
                 # sleep for a while
                 seek(GWFILE, $curpos, 0);  # seek to where we had been
               }

       If this still doesn't work, look into the POSIX module.  POSIX defines the clearerr() method, which
       can remove the end of file condition on a filehandle.  The method: read until end of file, clearerr(),
       read some more.  Lather, rinse, repeat.

       There's also a File::Tail module from CPAN.