Global symbol requires explicit package..

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

Hello , I want to say I am sorry first, because I criate one topic confusied..I do not speak english very well, and I am noob in perl, so I need more patience from you....So, I coded:

#!/usr/bin/perl
use strict;
use warnings;
my $sys="$^O";if ($sys eq linux) { $lim="clear";} else { $lim="cls"; }
print "hello";
my $ts=<STDIN>;
print "$ts";
system("$lim");
[download]

So when I run:Global symbol "$lim" requires explicit package name at /root/Desktop/exemplo.pl line 4;4;8. Bareword "linux" not allowed while "strict subs" in use at /root/Desktop/exemplo.pl

What is wrong? Thanks and sorry.

Comment on Global symbol requires explicit package.. Download Code

Replies are listed 'Best First'.
Re: Global symbol requires explicit package.. by SuicideJunkie (Vicar) on Jan 21, 2014 at 18:10 UTC
At line 4 you use `$lim`, and it isn't declared anywhere with `my` Also at line 4, you have a strange word `linux` which isn't a keyword and isn't defined as a sub anywhere either. You probably want to put quotes around that to make it a string.	[reply] [d/l] [select]
Re: Global symbol requires explicit package.. by Eily (Monsignor) on Jan 21, 2014 at 18:12 UTC
`use strict;` generates errors for some features / construct that are judged unsafe. More info on that in strict. And you can look at perldiag for more information on what the error messages mean. For exemple, the first one means : (F) You've said "use strict" or "use strict vars", which indicates that all variables must either be lexically scoped (using "my" or "state"), declared beforehand using "our", or explicitly qualified to say which package the global variable is in (using "::"). You should declare $lim before using it. With a `my $lim,` for exemple. The second one means that since there are no quotes around 'linux', it should (because of strict) be interpreted by Perl as a function and not a string, but there's no function called linux in your code. If you want a string, write `"linux"`.	[reply] [d/l] [select]
Re: Global symbol requires explicit package.. by Laurent_R (Canon) on Jan 21, 2014 at 18:19 UTC
Try to change your code this way: `my $sys = $^O; my $lim; if ($sys eq "linux") { $lim="clear"; } else { $lim="cls"; } # ...` [download] You actually don't really need the $sys variable, you could compare dirfectly $^O, but it does not matter.	[reply] [d/l]
Re^2: Global symbol requires explicit package.. by tobyink (Canon) on Jan 22, 2014 at 10:12 UTC
Indeed; the whole thing could be written as: `my $lim = ($sys eq 'linux') ? 'clear' : 'cls';` [download] `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l]
Re^3: Global symbol requires explicit package.. by choroba (Cardinal) on Jan 22, 2014 at 10:23 UTC
As noted by Tux in Re^2: Global symbol requires explicit package... I also like the hash switch solution if there are more possibilities than one: `my $lim = { linux => 'clear', BASIC => 'clrscr', }->{$^O} \|\| 'cls';` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re: Global symbol requires explicit package.. by meanroc (Acolyte) on Jan 21, 2014 at 18:54 UTC
Thak you so much guys..Now works.I do not need to delete the topic right??	[reply]
Re^2: Global symbol requires explicit package.. by Tux (Canon) on Jan 21, 2014 at 19:00 UTC
NO! Do not delete it. Others might have the same question and learn :) I'd write it even shorter: `my $lim = $^O eq "linux" ? "clear" : "cls";` The code you posted doe not past strict btw. So it must be changed before you ran it. Under strict, the bareword `linux` is not allowed. BTW, do not change the original post either :) Enjoy, Have FUN! H.Merijn	[reply] [d/l] [select]
Re^3: Global symbol requires explicit package.. by Laurent_R (Canon) on Jan 21, 2014 at 19:50 UTC
So would I, but I wanted to stick as much as possible to the OP's code, so that he or she could see the required changes.	[reply]