CODEWITHSUNDEEP
perlunixcommand-line
Angelo Uitz
Angelo Uitz

Reputation: 87

How to call subroutines with parameters from unix shell

I am working with different subroutines of a Perl script. It is possible to call a single subroutine from the Perl script via the Unix shell like:

simplified examples:

perl automated_mailing.pl inf

then the function inform_user from automated_mailing.pl gets called. This is realized through a dispatch table:

my %functions = (
  inf=> \&inform_user,
);

inform_user looks like

sub inform_user{
    print "inform user: Angelo";

    ...some other stuff...
}

The question now is, how to replace "Angelo" with a variable and call it from shell like:

sub inform_user{
    my ($to)=@_;
    print "inform user: $to";
}

This call does not work:

perl automated_mailing.pl inf("Brian")

How is this be done correctly?

Upvotes: 3

Views: 313

Answers (2)

Angelo Uitz
Angelo Uitz

Reputation: 87

With the given hint i reached exactly what i wanted. the programm now looks like:

use warnings;
use strict;

sub inform_user{
    my @to = @ARGV;
    print "inform user: $to[0]";
}

my %functions = (
  inform_user=> \&inform_user,
);

my $function = shift;

if (exists $functions{$function}) {
  $functions{$function}->();
} else {
  die "There is no function called $function available\n";
}

and the output is:

>> perl automated_mailing.pl inf Brian
>> inform user: Brian

Upvotes: 0

Dave Cross
Dave Cross

Reputation: 69244

  1. You need to pass the arguments as separate command-line parameters:

    perl automated_mailing.pl inf Brian

  2. You need to pass the command-line parameters onto the subroutine that you call:

    my ($func, @args) = @ARGV;

# And then later...

if (exists $functions{$func}) {
  $functions{$func}->(@args);
} else {
  die "$func is not a recognised function\n";
}

You haven't shown the code for the actual use of the dispatch table - so my second point is a bit of guesswork.

Upvotes: 4

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