在下面的小代码中，我没有收到行 [09] 和 [18] 的错误或警告。我得到的唯一警告是第 [21] 行：
use strict; # [01]
use warnings FATAL => 'unopened'; # [02]
# [03]
open(my $outHandleA, ">outputA.txt") or die ("A: $!\n"); # [04] Opened $outHandleA
print $outHandleA "FILE A\n"; # [05]
close $outHandleA; # [06] Closed $outHandleA
# [07]
print $outHandleA; # [08]
print $outHandleA "ABC\n"; # [09] <---
print $outHandleA; # [10]
print "-----"; # [11]
# [12]
open(OUT, ">outputB.txt") or die ("B: $!\n"); # [13] Opened OUT
print OUT "FILE B\n"; # …在Perl中，无引号的单词似乎有很多含义。
print STDERR $msg;
$hash{key}
func( param => $arg )
my $x = str;
如何确定这些含义？
执行以下简化代码时：
use strict; # [01]
use warnings FATAL => 'unopened'; # [02]
# [03]
my ($inHandle, $outHandle) = (\*STDIN, \*STDOUT); # [04]
print $outHandle "STDOUT 1\n"; # [05]
# [06]
# $outHandle re-assigned to outputA.txt ??? # [07]
open($outHandle, ">outputA.txt") or die ("A: $!\n"); # [08]
print $outHandle "FILE A\n"; # [09]
print "STDOUT? 2\n"; # [10]
print STDOUT "STDOUT 3\n"; # [11]
close $outHandle; # [12]
# [13]
# $outHandle is closed # [14]
print STDOUT "STDOUT 4\n"; # …