Anything comparable to argv0 from C in Perl?

brianarn has asked for the wisdom of the Perl Monks concerning the following question:

Hello, I'm relatively new to perl but not programming, and I'm learning this wonderful language now :) but I'm trying to do something, and I'm a little stuck. I have the O'Reilly's stuff but maybe I'm just not searching it right.

Anyways, here's the question.

In C/C++ there's the ARGC and ARGV variables, which I understand that @ARGV is like ARGV in C. However, ARGV[0] is the first argument given in Perl, whereas it's the executable name in C. Is there a way to get the name of the perl script I'm running, so I can generate some sort of message instructing the user on usage? For example...

#!/usr/local/bin/perl
use strict;
if (@ARGV != 2) {
    print "Usage: (program name) arg1 arg2\n";
    exit;
}
[download]

I tried ARGV[0] by instinct from C and, of course, got the first argument I called the function with - blew my mind till I did for (@ARGV) {print "$_\n}; and saw that it didn't have the script name.

Any help? Thanks.

Brian, relatively new perlmonk

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(tye)Re: Anything comparable to argv0 from C in Perl? by tye (Sage) on Apr 11, 2001 at 00:06 UTC
Type the command perldoc perltrap and read. There is a section for people moving from C to Perl. - tye (but my friends call me "Tye")	[reply]
Re: Anything comparable to argv0 from C in Perl? by japhy (Canon) on Apr 11, 2001 at 00:01 UTC
Check perlvar for the `$0` variable. `japhy` -- Perl and Regex Hacker	[reply]
Re: Anything comparable to argv0 from C in Perl? by satchboost (Scribe) on Apr 11, 2001 at 00:00 UTC
Try $0. Have you read the Camel book? I'd reccommend that, as well as Advanced Programming in Perl. Both are available from O'Reilly.	[reply]
Re: Anything comparable to argv0 from C in Perl? by jink (Scribe) on Apr 11, 2001 at 22:10 UTC
I usually use this to get only the last part of your script name: `#!/usr/bin/perl -w use strict; my @a=split(/\//,$0); my $myname=pop @a; if ($#ARGV != -1) { die "Usage: $myname parameters\n"; }` [download]	[reply] [d/l]
Re: Re: Anything comparable to argv0 from C in Perl? by DrManhattan (Chaplain) on Mar 13, 2003 at 21:38 UTC
Here's a one-liner to extract the base name from the full path without a temporary array: `my ($basename) = $0 =~ m/.\/(.)/;` [download] You can also use split() like this: `my $basename = (split /\//, $0)[-1];` [download] -Matt	[reply] [d/l] [select]