#!/usr/bin/perl

if ($#ARGV<2 || $#ARGV>3) {
  print "usage: SubStr.pl <param> <string> <start> [<bytes>]\n";
  exit();
}

my $SubStr = "";

my ($Param, $String, $Start, $Bytes) = @ARGV;

if ($Bytes) {
  $SubStr = substr($String, $Start, $Bytes);
} else {
  $SubStr = substr($String, $Start);
}

print "\$$Param = $SubStr\n";