I know about inodes

But the question remains:

How can I revive/move an "invisible" file into the directory?

link doesn't seem to accept FHs.

use strict;
use warnings;
use Data::Dump qw/ddx/;
use autodie;



my $dir  = "/tmp";
my $file = "$dir/tst_unlink";

open my $fh, ">>", $file;

print $fh "ENTRY ".__LINE__;

ddx <$file*>;

unlink $file;

print $fh "ENTRY ".__LINE__;

ddx <$file*>;

eval { link $fh, "${file}_new"; } or warn $@;

eval { link $file, "${file}_new"; } or warn $@;


ddx <$file*>;

__DATA__
[download]

# open_unlink.pl:16: "/tmp/tst_unlink"
# open_unlink.pl:22: ()
Can't link($fh, '/tmp/tst_unlink_new'): Datei oder Verzeichnis nicht g
+efunden at ./open_unlink.pl line 24
Can't link('/tmp/tst_unlink', '/tmp/tst_unlink_new'): Datei oder Verze
+ichnis nicht gefunden at ./open_unlink.pl line 26
# open_unlink.pl:29: ()
[download]

PS: FWIW: I was guessing, I can't run a full diagnosis for every fuzzy bug question, even after reading it thrice.