Setting default values in getopts

[neilwatson]

Givers of wisdom and knowledge please consider my humble questions:

How does one set default values of command line arguements?

use Getopt::Std;

my %opt;
my $opt{d} = "x";
my $opt{a} = "0";
my $opt{s} = "0";
my $opt{e} = "x";
getopts("dase:", \%opt);

Using something like this returns a syntax error at my $opt{d}="";. What have I done wrong?

Neil Watson
watson-wilson.ca

[jeffa]

You can't redeclare a variable with my as you are doing. In fact, the better way to declare %opt is with use vars, like so:

use vars qw(%opt);
$opt{d} = "x";
$opt{a} = "0";
$opt{s} = "0";
$opt{e} = "x";
getopts("dase:", \%opt);

Good luck!

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

[neilwatson]

Thanks, that did the trick.

Neil Watson
watson-wilson.ca

[Fletch]

Aside from jeffa's point about you re-my'ing things, you might want to use something like this instead of multiple assignments:

my %opt = (
            d => "x",
            a => 0,
            s => 0,
            e => "x",
           );

[maverick]

jeffa is quite right...here's what I tend to do, since the next natural thing is to assign each option out into a meaningfully named scalar

my %opts;
getopts("d:a:s:e:", \%opt);
my $Directory = $opts{'d'} || '/home/maverick';
my $Address   = $opts{'a'} || '[e-mail]';
my $Silent    = $opts{'s'} || 0;
my $Extended  = $opts{'e'} || 0;

This way I don't have to remember what's in $opts{'d'} and neither does whoever reads my code later. Plus the defaults are really easy to spot.

/\/\averick
perl -l -e "eval pack('h*','072796e6470272f2c5f2c5166756279636b672');"