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Date: Wed, 30 Jun 2004 12:49:22 -0500
From: Josh Paetzel <friar_josh@tcbug.org>
To: Drew Tomlinson <drew@mykitchentable.net>
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cc: FreeBSD Questions <freebsd-questions@freebsd.org>
cc: Steve Bertrand <steveb@eagle.ca>
Subject: Re: Perl Syntax
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> >>I'm using perl 5.8.4 on a 4.9 machine.  I want to add code a perl script
> >>to check for value passed from command line.  If it is null, I want to
> >>exit with an error message.
> >>
> >>First I tried this and got "Use of uninitialized value in string eq at
> >>./test.pl line 20."
> >>
> >>if ($ARGV[0] eq "") {
> >> print "You must include the file name.";
> >> exit 1;
> >>}
> >>
> >>Next I tried this but get "Use of uninitialized value in length at
> >>./test.pl line 20."
> >>
> >>if (length ($ARGV[0]) = "0") {
> >> print "You must include the file name.";
> >> exit 1;
> >>}
> >>
> >>I've searched the web and all examples that I've found indicate that I'm
> >>doing things correctly but obviously I'm not.  What am I doing wrong?
> >>
> >>   
> >>
> >
> >I know this works:
> >
> >if ($ARGV[0] eq '') {
> >       print "Debug Mode\n";
> >}
> >
> >Cheers,
> >
> >Steve
> >
> Thanks for your reply.  I tried your suggestion and it seems to work but 
> I get this output:
> 
> Use of uninitialized value in string eq at ./test.pl line 16.
> You must include the file name.
> 
> I have "use warnings;" and "use strict;" in the script.  I assume the 
> error comes from the "use warnings;" but why does perl see "eq" as a 
> string and not an operator?  Or am I misinterpreting the message?
> 
> Thanks,
> 
> Drew
> 

#!/usr/bin/perl -w

if (!ARGV[0]) {
	print "no arguements\n";
}

else {
	print "found an arguement\n";
}

Josh Paetzel