Perl GetOptions module

Question

I have a script which takes up 3 input variables from CLI and insert it to 3 variables respectively:

GetOptions("old_path=s" => \$old_path,
       "var=s"      => \$var,
       "new_path=s" => \$new_path,
       "log_path=s" => \$log_path)
or die ("Error in input variables\n");e

Is there a way in which I can add a subroutine or any other GetOptions parameter which explains how to give the input variables. Please correct me if any mistake. Thank you.

Answer 1

The standard way in Perl is to use Pod::Usage as recommended in Getopt::Long. A complete example is shown in Documentation and help texts

Answer 2

It sounds like you're looking for Getopt::Long::Descriptive.

Answer 3

Try this, we can define HelpMessage subroutine with print statements what we want to show for command help,

    GetOptions("old_path=s" => \$old_path,
               "var=s"      => \$var,
               "new_path=s" => \$new_path,
               "log_path=s" => \$log_path,
                "help" => sub { HelpMessage() })
                 or die ("Error in input variables\n");