#!/usr/bin/perl
# Tom Blum
# May 2007
# IWA-HWG Homework/ Instructor M. Kowalski

	#print out contents of the environment hash
	while( ($key, $value) = each %ENV)
	{
		print "$key => $value\n";
	}

	#make a copy of the environment hash
	%env_copy = %ENV;
	print "\nCopied.\n";
 	
	#change some values in the copy of the environment hash
	$env_copy{"HOMEDRIVE"}="D:";
	$env_copy{"TEMP"}="D:\\temp";
	$env_copy{"TMP"}="D:\\temp";
	
	
	#print out contents of the copy of the environment hash
	foreach $i (keys %env_copy) 
	{
		chomp($env_copy{$i});
		print "$i: $env_copy{$i}\n";
	}


	
	#delete $env_copy{"PATH"};  #deletes PATH vriable so can test else
	if(exists $env_copy{"PATH"})
	{
		print "\nFound PATH\n";
		print "The PATH environment variable lets the computer know\n";
		print "where to look for executable files, such as those with\n";
		print "extensions like .exe, .com, and .bat. When a command \n";
		print "is invoked from the command line, the computer looks \n";
		print "for the corresponding file in the local directory, as \n";
		print "well as the locations indicated by the PATH variable.\n";  
	}
	else
	{
		print "Did not find PATH\n";
		print "Let us add one.\n";
		$env_copy{"PATH"}="D:\\temp";
	}

	print "\n\nYour PATH is: $env_copy{'PATH'}\n\n";

	#delete some key/value pairs from hash
	delete $env_copy{"HOMEPATH"};
	delete $env_copy{"POOP"}; #see what happens if remove something that doesn't exist
	delete $env_copy{"PROCESSOR_REVISION"};

	print "\nAfter Removing\n\n";
	#print out contents of the copy of the environment hash
	foreach $i (keys %env_copy) 
	{
		chomp($env_copy{$i});
		print "$i: $env_copy{$i}\n";
	}