#!/usr/bin/perl -w
#didn't use strict, to make the example clearer.

$foo = 3; 	#default value of $foo

{	

local $foo = 5;	#now the value of $foo is 5 while inside the braces

print "$foo\n";	# prints 5.
}

print "$foo\n";	# prints 3.

##</code><code>##

#!/usr/bin/perl -w
use strict;    #<- very important.

my $foo = 3;  # $foo has a value of 3, and is seen by the compiler.

{

my $bar = 5;  # $ bar life is limited to the block.
print "$bar\n"; # you get 5.
print "$foo\n";	# you get 3.

}
print "$bar\n"; # <- compiler gives error.$bar does not exsist (kind of).
print "$foo\n";	# you get 3.

##</code><code>##

s/compiler/interpreter/ig;