using arguments when running a script

[unixrookie]

Can perl take arguments off of the command line and choose different variables based on what argument is given. for example can.

showan.pl -h LA

could that call a perlscript which has a bunch of variables in it and based on the "LA" given after the -h call the variable $LA = "la1-7200"

i'm trying to use one perl script that has multiple hosts in it as variables. i want the same script to run on different hosts depending on the -h argument? Any and all help is appreciated. i'm open to other suggestions as well.


Mark

 

[MikeLacey]

Hi Mark,

Yes. Perl can take values from the command line, like this.

my $switch = shift;

That takes the first argument, in your example that would be -h

my $host = shift;

That takes the second argument, in your example that would be LA

Why do you need a variable *called* $LA? You can do that, but it's fiddly and not usually needed.
Mike
________________________________________________________________

"Experience is the comb that Nature gives us, after we are bald."

Is that a haiku?
I never could get the hang
of writing those things.

 

[flawless69]

As well as shift, you can also use the special array @ARGV to access command line args. $ARGV[0] is the first argument in the command line. A note on this is that to check for no command line arguments you must check to see that $#ARGV is < 0. i.e. $#ARGV is the number of arguments - 1.

These are just extra ramblings though....use shift. --Derek

&quot;Fear not the storm for this is where we grow strong.&quot;

 

[unixrookie]

WOW that was so easy. Thanks to both of you for your help.

How many arguments can i call from the command line like this

Mark

 

[justice41]

If you are going to be using several command line switches then it's more practical to use a Perl module that will parse switches for you. Either Getopt::Std or Getopt::Long is simple to use. For example Getopt::Std will set a variable (or a hash key if you pass it a hashref) that contains the value after the switch (or 1 if the switch doesn't take an argument). Here's an example:

use strict;
use Getopt::Std;

my $LA;
our ($opt_h, $opt_s);

getopt('hs');

if (defined $opt_h) {
        $LA = $opt_h;
}
if (defined $opt_s) {
        # so something here for -s
}

Then none of the switches or their arguemnts appear in @ARGV, only true command line arguments do.

 

[unixrookie]

Excellent!
I tried all the suggestion and was able to make them all work. The help here is invaluable. Thanks again
Mark