GetOptions("file=s" => \$file);

      


use Getopt::Long;

GetOptions("file=s"  => \$file);

if ($file) {
    print "File name: $file\n";
}

1.	Simple options
2.	Generate random passwords?
3.	Extract command-line switches with Getopt::Std
4.	Perform consistent command line parsing
5.	Process complex command lines
6.	Read from a file
7.	To turn a feature on or off. Use the exclamation point(!)
8.	Using Getopt to deal with command line options
9.	getopt('pMN');
10.	If the value is optional, use a colon
11.	For a text string value, use :s for an optional value or =s for a required value:
12.	Check if a file exists
13.	A double dash (--) by itself signals the end of the command-line switches.

GetOptions("file=s" => \$file); : Getopt « System Functions « Perl