#!/usr/bin/perl
use Fcntl qw(:DEFAULT :flock);
$|=1;
if (!defined($child_pid = fork())) {
	die "cannot fork: $!";
} elsif ($child_pid) {
	# I'm the parent
	$file="file.txt";
	while ( 1 == 1 ) {
		$input = <STDIN>;
		chomp($input);
		# repeat what was entered st stdin.. then open file.txt, lock it so others
		# leave it alone, read it and close it, so others can use it again
		print "$input\n";
		open FH, "<$file"or die "Cannot open $file for read :$!";
		flock(FH, LOCK_SH)  or die "can't lock filename: $!";
		while (<FH>) {
			print "      $_";
		}		
		close FH;
	}
} else {
	# I'm the child
	$file="file.txt";
	while ( 1 == 1 ) {
		#get some info from a process that can be slow, see if file.txt is locked
		#if not, then open/create the file.txt and write info, and close file.
		#sleep and repeat
		@info = `snmpwalk -v 1 -c public $novell_srv .1.3.6.1.4.1.23.2.28.3.8.1.2`;
		sysopen(FH, $file, O_WRONLY | O_CREAT) or die "can't open $file: $!";
		flock(FH, LOCK_EX) or die "can't lock $file: $!";
		truncate(FH, 0) or die "can't truncate $file: $!";
		print FH "@info";
		truncate(FH, tell(FH)) or die "can't truncate $file: $!";
		close(FH) or die "can't close $file: $!";
		sleep 5;
	};
}