Requiring option values in Getopt::Long

bichonfrise74 has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

This could be a very simple question but I was trying to super search this question in perlmonk but could not find the answer. Also, I tried to search the Getopt::Long documentation but to no avail.

Basically, I want the code to give an exit if the value to the optional argument was not supplied. I have this code.

#!/usr/bin/perl

use warnings;
use strict;
use Getopt::Long;

my ($option_test);
GetOptions( "test=s" => \$option_test );

print 'option is not defined.' if ( ! $option_test );
[download]

See below what happens when I run the code above.

$ test.pl
option is not defined.

$ test.pl -t
Option test requires an argument
option is not defined.
[download]

So, the 2 tests above shows that if I do not supply a proper argument to the -t option, then it is as if I did not use the -t option at all.

What I want is for Getopt::Long to exit if it gives this message "Option test requires an argument".

Thanks in advance.

Comment on Requiring option values in Getopt::Long Select or Download Code

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Re: Requiring option values in Getopt::Long by markkawika (Monk) on Aug 20, 2009 at 00:04 UTC
Getopt::Long will not exit for you; it will warn you (and the user) about the error, but it's up to you to exit if there was a problem. Be sure to check the return value from GetOptions: `use Getopt::Long; my $option_test; my $result = GetOptions ( 'test=s' => \$option_test ); if (! $result) { die "Invalid option specifications"; }` [download] Example: $ ./getopt.pl -t Option test requires an argument Invalid option specifications at ./getopt.pl line 9. $ [download]	[reply] [d/l] [select]
Re: Requiring option values in Getopt::Long by toolic (Bishop) on Aug 20, 2009 at 00:28 UTC
See also: Getopt::Long > Return values and Errors	[reply]
Re: Requiring option values in Getopt::Long by JavaFan (Canon) on Aug 20, 2009 at 00:06 UTC
What I want is for Getopt::Long to exit if it gives this message `GetOptions( "test=s" => \$option_test ) or exit;` [download]	[reply] [d/l]
Re: Requiring option values in Getopt::Long by bichonfrise74 (Vicar) on Aug 20, 2009 at 02:54 UTC
I re-read the documentation again and figured out that this code actually solves what I want. `#!/usr/bin/perl use warnings; use strict; use Getopt::Long; my ($option_test); my $check_option = GetOptions( "test=s" => \$option_test ); die 'Invalid option' if ( $check_option ne 1 ); print "next line";` [download] Here's the result when I ran some tests. `$ test.pl next line $ test.pl -t abc next line $ test.pl -t Option test requires an argument Invalid option at test.pl line 9.` [download] Thank you all for your help.	[reply] [d/l] [select]
Re^2: Requiring option values in Getopt::Long by ikegami (Patriarch) on Aug 20, 2009 at 03:27 UTC
Why the redundant error error message? A cleaner version was previously suggested to you. `GetOptions( 'test=s' => \$option_test ) or exit(1); defined($option_test) or die("Missing argument -t");` [download] At the very least, remove the line number from the error message. It's useless clutter. `GetOptions( 'test=s' => \$option_test ) or die("Invalid command-line option\n"); defined($option_test) or die("Missing argument -t\nInvalid command-line option\n");` [download] However, I suggest that you display a useful error message instead: `use File::Basename qw( basename ); sub help { my $prog = basename($0); print("usage: $prog -t [options]\n"); exit(0); } sub usage { my $msg = shift \|\| ''; my $prog = basename($0); die("${msg}Use $prog --help for help\n"); } GetOptions( 'help\|h\|?' => \&help, 'test=s' => \$option_test, ) or usage(); defined($option_test) or usage("Missing argument -t\n");` [download]	[reply] [d/l] [select]
Re^3: Requiring option values in Getopt::Long by zwon (Abbot) on Aug 20, 2009 at 18:31 UTC
I usually prefer to write documentation for script as POD and then use Pod::Usage to show help message.	[reply]
Re: Requiring option values in Getopt::Long by bichonfrise74 (Vicar) on Aug 20, 2009 at 16:54 UTC
Hmm, I tested the code of JavaFan last night and I thought it didn't work. I was wrong because it did work and I was probably too sleepy to test it out properly. Anyway, thanks JavaFan and ikegami for the help.	[reply]
Re^2: Requiring option values in Getopt::Long by Anonymous Monk on Oct 08, 2010 at 21:46 UTC
I've tried the sample script: #!/usr/local/bin/perl use Getopt::Long; my $option_test; my $result = GetOptions ( 'test=s' => \$option_test ); if (! $result) { die "Invalid option specifications"; } on two different platforms (OS X and Ubuntu, both perl 5.10) and in both cases Getopt is returning 1 (success) _even if_ the supposedly required parameter isn't provided. has this behavior in Getopt changed?	[reply]