Getopt::Long and default number

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

I've started using Getopt::Long for a little script I'm creating. I'm having trouble figuring out how to give an option a default value if it is specified. For example:

shell$ progname
  $opt == 0
shell$ progname --opt
  $opt == 100
shell$ progname --opt 7
  $opt == 7
[download]

Or more verbosely, if --opt isn't specified, I want it to be 0. If --opt is specified, but not given any number, I want $opt to hold 100, and if --opt is specified with a number, I want $opt to hold the number specified.

This is probably really easy, but I must be missing it. Has anybody done this before?

-Bryan

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Re: Getopt::Long and default number by jimbojones (Friar) on Jul 19, 2005 at 18:41 UTC
Hi I think you want the ":" signifier when identifying your options. This says the value for the option is optional. If the option is present without a value, it takes the number indicatied after the ":" ; otherwise it takes the user-supplied value. This is in the POD in the section "Summary of Option Specifications" `use Getopt::Long; my $opt = 0; GetOptions ("opt:100" => \$opt ); print "Opt is:\t$opt\n";` [download] My test runs give: `>opt.pl --opt Opt is: 100 >opt.pl --opt 7 Opt is: 7 >opt.pl Opt is: 0` [download] HTH - j	[reply] [d/l] [select]
Re^2: Getopt::Long and default number by mrborisguy (Hermit) on Jul 19, 2005 at 19:06 UTC
Bingo! Thanks! ++ -Bryan	[reply]
Re: Getopt::Long and default number by izut (Chaplain) on Jul 19, 2005 at 18:49 UTC
Try this: `my $opt = "0"; $result = GetOptions ("opt:s" => \$opt,); $opt = 100 if ($opt eq "");` [download] I'm pretty sure there are some better way to perform this task, but can't figure out how right now. surrender to perl. your code, your rules.	[reply] [d/l]