#!/usr/local/bin/perl -w

#A Perl version of the unix (tail -f) command
#written by Nick (see http://illx.org for more details)
#uses the 'trailing a growing file' from Perl Cookbook
#NOTE: This script DOES NOT print the last 10 lines of the
#file like tail does... it just reads a growing file

my $log = $ARGV[0];
unless($log) {
    print "Won't continue with an argument!\n",
    "Usage: ./perltail_f /var/log/mail.log\n\n";
    exit 1;
}

unless( -e $log ) {
    print "The logfile $log you specified doesn't exist, exiting...\n";
    exit 1;
}

use IO::Handle;
open(LOG, "$log") or die "Can't open $log: $!\n";

#seek to end of file
seek(LOG, 0, 2);

#and start watching it from there
for(;;) {
    while(<LOG>) { print }
    #change sleep for faster or slower updating
    sleep 1;
    LOG->clearerr();
}

close(LOG);