Changes

     my $var = "value";

     my $var = "value";

The my is actually not required; you could just use:

The '''my''' is actually not required; you could just use:

     $var = "value";

     $var = "value";

However, the above usage will create global variables throughout your program, which is bad programming practice. my creates lexically scoped variables instead. The variables are scoped to the block (i.e. a bunch of statements surrounded by curly-braces) in which they are defined.

However, the above usage will create global variables throughout your program, which is bad programming practice. '''my''' creates lexically scoped variables instead. The variables are scoped to the block (i.e. a bunch of statements surrounded by curly-braces) in which they are defined.

     my $x = "foo";

     my $x = "foo";

     print $y; # prints nothing; $y has fallen out of scope

     print $y; # prints nothing; $y has fallen out of scope

Using my in combination with a use strict; at the top of your Perl scripts means that the interpreter will pick up certain common programming errors. For instance, in the example above, the final print $y would cause a compile-time error and prevent you from running the program. Using strict is highly recommended.

Using '''my''' in combination with a '''use strict;''' at the top of your Perl scripts means that the interpreter will pick up certain common programming errors. For instance, in the example above, the final '''print $y''' would cause a compile-time error and prevent you from running the program. Using '''strict''' is highly recommended.

 

=== Conditional and looping constructs ===

=== Conditional and looping constructs ===