I have a somehow standard way of displaying help for my scripts:
I display the POD data using the $0 perl internal variable.
$0 (or $PROGRAM_NAME if you are using the use English; pragma) "contains the name of the file containing the Perl script being executed", to quote the Camel book.
The help section is printed on screen if a script requires a parameter but none has been provided. I used to write it this way for a command line accepting only one parameter:
sub get_help {
system("perldoc $0");
exit;
}
my $arg = $ARGV[0] || &get_help;However, I recently ran into a slight difficulty.
On Windows, $0 contains the disk letter followed by the complete path and finally the file name. For example:
C:\Users\Damien\Desktop\test coverage\Perl Scripts
Notice the white spaces in the directory names.
When trying to perldoc this particular file name, I would get an error stating that there is no documentation for "C:\Users\Damien\Desktop\test", "coverage\Perl" nor "Scripts".
My first reaction was simply to surround the $0 file name with "" as shown below:
sub get_help {
system("perldoc \"$0\"");
exit;
}
my $arg = $ARGV[0] || &get_help;[Added Dec. 29th]
However, an enlightened reader pointed me to the best solution:
sub get_help {
system("perldoc", $0);
exit;
}
my $arg = $ARGV[0] || &get_help;Using the list argument form of the system function avoids relying on the shell to run your command.
