| #!/usr/bin/env perl | |
| use strict; | |
| use warnings; | |
| # Only arguments '--exclusive 1' exactly are supported. | |
| (@ARGV == 2) or die; | |
| my $mode = shift; | |
| ($mode eq "--exclusive") or die; | |
| my $fd = shift; | |
| ($fd eq "1") or die; | |
| use Fcntl ':flock'; | |
| open(my $fh, '>&=', 1) or die "open: $!"; | |
| flock($fh, LOCK_EX) or die "flock: $!"; |