#!/usr/bin/perl

$FILE=$ARGV[0];
$find=$ARGV[1];
$replace=$ARGV[2];

if (! -e $FILE) {
	die "File not found: $FILE";
}

open(FILE,"$FILE");
open(FT,">$FILE.TMP");
while(<FILE>) {
	if (/$find/) {
		s/${find}($|\s|\t)/${replace}$1/g;
	}
	print FT $_;
}
close(FILE);
close(FT);

open(FT,"$FILE.TMP");
open(FILE,">$FILE");
while(<FT>) {
	print FILE $_;
}
close(FT);
close(FILE);
unlink("$FILE.TMP")