从perl脚本内部可以知道要将输出重定向到的文件的名称吗？

Question

So I have:

test.pl > test.log

is there a way to know inside test.pl that I am outputing to 'test.log'? At the end of my script I want to do some manipulation of test.log without hardcoding the name.

Answer 1

Maybe. The following works on Linux, but will not be very portable to other systems...

#!/usr/bin/env perl

use strict;
use warnings;

my $out = readlink("/proc/$$/fd/1");
print STDERR "I am being output to $out\n";

Naturally, this is probably a bad idea. Better to explicitly open the file and write to it in Perl, rather than having the shell set up redirections.

Answer 2

You can redirect standard output from perl, with minimal changes to your script,

test.pl test.log

---

my ($file) = @ARGV;
if (@ARGV) {
  open STDOUT, ">", $file or die $!;
}

print "output is redirected to $file\n";

# use $file at the end