... or die "Can't open $file"

Of course! Thank you!

Oh that was an embarrassing miss!

Hello hda,

LanX has answered your question, but I was somewhat surprised by the error message (which comes courtesy of use strict;, BTW), since it appears that $fh is already declared when the die code is parsed. Deparsing shows what’s going on: or is (apparently) rewritten as unless, which places the $fh in the die clause before its declaration in the call to open:

22:56 >perl -MO=Deparse -Mstrict -we "my $file = 'x'; open (my $fh, '<
+', $file) or die qq[Can't open $fh];"
Global symbol "$fh" requires explicit package name (did you forget to 
+declare "my $fh"?) at -e line 1.
-e had compilation errors.
BEGIN { $^W = 1; }
use strict;
my $file = 'x';
die "Can't open ${'fh'}" unless open my $fh, '<', $file;

22:56 >
[download]

Hope that’s of interest,

Perl makes "my" variables available in the statement after the "my". This allows things like

my $foo = 'Bar';
my $foo = $foo x 2;
say $foo; # 'BarBar'
[download]

No, I do not defend this as a coding practice -- I'm just trying to elucidate how Perl works.

"...This allows things like..."

Yes and no:

#!/usr/bin/env perl

use strict;
use warnings;
use feature qw(say);;

my $foo = 'Bar':
my $foo = $foo x 2;

say $foo;

__END__
[download]

Perl allows it generously but then it complains about  "my" variable $foo masks earlier declaration in same scope at ./foo.pl line 8..

Iznogoud. But in a block it works flawless - no surprise:

KARL : {
    my $foo = $foo x 2;
    say $foo;
}
[download]

But why the effort? You could say $foo x= 2; which results in BarBar. If this is what you wanted. What i assume.

Best regards, Karl

«The Crux of the Biscuit is the Apostrophe»

perl -MCrypt::CBC -E 'say Crypt::CBC->new(-key=>'kgb',-cipher=>"Blowfish")->decrypt_hex($ENV{KARL});'Help

It's pretty useful in nested scopes and closures.

For instance

my $level = $level + 1;

Very Strange, But if it worked the way I expect, perl would not have found the error.
Bill