Welcome to the Monastery, mbravismore!

Normally, I'd skip such a question due to no effort shown whatsoever (please do so in the future), but I thought I'd at least show a basic skeleton that you can at least get started with. See the documentation of Getopt::Long to get an understanding of what is happening. You'll want/need to add in some parameter checking to ensure all required arguments are passed in.

use strict;
use warnings;

use Getopt::Long;

my %args;

GetOptions (
    'i|txtpatid=s' => \$args{txtpatid},
    'p|txtpatpw=s' => \$args{txtpatpw},
    's|txtpatserver=s' => \$args{txtpatserver},
);

for (keys %args){
    print "$_: $args{$_}\n";
}
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Run it:

perl script.pl -i stevieb -p secret -s user
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Output:

txtpatid: stevieb
txtpatpw: secret
txtpatserver: user
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