Examples of simple Perl programs

Examples adapted from
Computer Science & Perl Programming: Best of the Perl Journal
Edited by Jon Orwant
O'Reilly, 2003
Chapter 7: What is Truth, by Nathan Torkington

0. #!/usr/bin/perl -w
   print $x

1. 	
   #!/usr/bin/perl -w
   print $x 

   Note: blank line at top of file
   

2. #!/usr/bin/perl -w
   $x = 7;
   print $x;

3. #!/usr/bin/perl -w
   $x = 7;
   print "$x\n";

4. #!/usr/bin/perl -w
   if (defined $x) {
   print "x has value $x\n";
   } else {
   print "x is undefined\n";
   }