option on command line

[Sara]

Hello guys , how can I do this : I am runing my script passing it the -u option , user must use -u <file> to run the script ,,

perl myScript -u <file>

I would like to add another option like -x -m but I want them to be optional ,,, if the user doesn't pass them then it is fine thanks

[mfriedman]

Getopt::Std and Getopt::Long are very useful for parsing command line options.

[larsen]

For this kind of purposes, I use Getopt::Mixed.

#!/usr/bin/perl

use strict;

use Getopt::Mixed;

use vars qw|$opt_u $opt_x $opt_m|;
# Note that you have to use globals...

Getopt::Mixed::getOptions( qq|u=s x:i m:i| );
# Option u wants (mandatory) a string
# Option x accepts (not mandatory) an integer
# Option m too...

die "Hey man, you have to provide an username!\n" unless $opt_u ;
print "Option 'u' is $opt_u\n";

Now your script will accept options from the command line, storing them in globals and complaining if you use options without their mandatory argument (i.e., you can't use a bare -u on the command line).

What makes Getopt::Mixed interesting is the possibility to specify longer synonyms for options. So, you can change a line of the script in this way:

Getopt::Mixed::getOptions( qq|u=s username>u x:i m:i| );

username is a synonym for u, so that you can call your script from commandline is these two ways with the same results:

# getopt.pl -u larsen
Option 'u' is larsen

# getopt.pl --username larsen
Option 'u' is larsen

Update: Added an error message in case the user does not provide -u option

[Nightblade]

Sara, you could paste sample of your code, that we could know where is problem.

You can do something like that:


use Getopt::Std;
getopts('u:x:m:', \%Opts)
$file = $Opts{'f'} or die "Where is your file?";
$x = $Opts{'x'};
$m = $Opts{'m'};


-f is required, -x and -m is optional,

[BazB]

You should look at your code and simply extend the existing functionality using which ever method is being used already (likely Getopt::Std), unless you expect your argument parsing requirements to become substantially more complex, in which case the modules suggested by mfriedman and larsen will be of interest.

On a related note, I notice that you have posted a number of SoPW's simply asking fellow Monks to craft code to solve (what appear to be related) problems.
You should make the effort to understand the code you are faced with, then try to resolve the problem yourself - post your attempts, even if they are faulty!
You should find that as you spend more time attempting to fix your own problems you should become familiar with basic functions and modules and it will much easier for you to program once you have that understanding.

Cheers.

BazB

[zentara]

Hi, GetOpts is probably your best bet, but in case you
want to do it without a module, try something like this.


#!/usr/bin/perl
use warnings;
use strict;

my $usage = "Usage: script -u username -x xval(optional) -m mval(optio
+nal)\n";
my $username=undef;
my $xvalue=undef;
my $mvalue=undef;

while(@ARGV){
   my $argin = shift;
   if ($argin =~ /-u/){$username= shift}
   if ($argin =~ /-x/){$xvalue=shift}
   if ($argin =~ /-m/){$mvalue =shift}
}

if ( !defined $username ){print $usage;exit;}
print "username = $username\n -x = $xvalue\n -m = $mvalue\n";

[thor]

I'm a big fan of the ternary operator in cases like this.

$var_for_opt_a = defined($opt_a) ? $opt_a : "some default value";

As the others said above, use one of the GetOpt modules as well.

thor