#!/usr/bin/perl -w
print "Enter the name of your file, ie myfile.txt:\n";
my $val = <STDIN>;
chomp ($val);
my $cnt=0;
open (HNDL, "$val") || die "wrong filename";
while ($val = <HNDL>)
	{
	  while ($val =~ /\bchr1\b/ig)
	  {
		++$cnt;
	  }
	} 
print "Number of instances of 'chr1' found: $cnt\n\n";