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Perl GetOptions: Undefined argument in option spec

Hi guys, hope u r all well.

Guys im trying to learn how to read command line arguments by using the GetOpt module, but each time i run the following examples, which im assuming "should" work im getting an error saying:

"Undefined argument in option spec"

Here are the examples:

================================================================= example1.pl
#!/usr/bin/perl
# import module
use Getopt::Long;
# read options
$result = GetOptions ("age=i" => $age);
# print value
if ($age) { print "Input age is $age years"; }

================================================================= example2.pl
#!/usr/bin/perl

# import module
use Getopt::Long;
# read options
$result = GetOptions ("name=s" => $name);
# print value
print "Input name is $name";

When I run these examples with or without options specified, im getting the following...

Undefined argument in option spec

Id love to know what is happening.

Thank you :>)

ASKER CERTIFIED SOLUTION

hielo

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Simon336697

ASKER

You are so fast and so generous hielo....ill give that a go mate

Simon336697

ASKER

hielo,

I tried the following the code snippet, and get the following message:

Name "main::result" used only once: possible typo at /simon_data/scripts/age_getoptions.pl line 5.

 #!/usr/bin/perl -w
 # import module
 use Getopt::Long;
 # read options
 $result = GetOptions("age=i" => \$age);
 # print value
 if ($age) { print "Input age is $age years"; }

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Simon336697

ASKER

hielo,
I think ive got it but dont understand why...

I gave $result an initial value
eg.
$result =0

 #!/usr/bin/perl -w
 # import module
 use Getopt::Long;
 # read options
 $result = 0;
 $result = GetOptions("age=i" => \$age);
 # print value
 if ($age) { print "Input age is $age years\n"; }

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hielo

From that page:
my $verbose = ''; # option variable with default value (false)
my $all = ''; # option variable with default value (false)
GetOptions ('verbose' => \$verbose, 'all' => \$all);

I would have expected you to initialize $age rather than $result.

Simon336697

ASKER

hielo,
You are brilliant mate.

I found this other example here:

#!/usr/bin/perl

# import module
use Getopt::Long;

# set default value for option
$debug = 0;

# get value of debug flag
$result = GetOptions ("debug" => $debug);

# print value
print "Debug flag is $debug";

from following page:

http://www.devshed.com/c/a/Perl/Processing-Command-Line-Options-with-PERL/2/