#!/usr/bin/perl
use warnings;
use strict;
use constant TRUE  => 1;
use constant FALSE => 0;
use Linux::Inotify2;
use IO::Handle;

open my $fh, '<', $ARGV[0]  or  die "Cannot open file: $!\n";
$fh->blocking( FALSE );

my $inotify = new Linux::Inotify2  or  die "Unable to creat Linux::Inotify2 object: $!\n";
$inotify->watch( $ARGV[0], IN_MODIFY, \&file_changed )  or  die "watch creation failed";
sub file_changed {
    while ( sysread $fh, my $buff, 50 ) {
        syswrite STDOUT, $buff;
    }
}

print <$fh>;
1 while $inotify->read;
close $fh;