fix: batch: don't attempt to read if stdin is closed

bin/plugin/open/batch

@@ -2,6 +2,8 @@
 # vim: set filetype=perl ts=4 sw=4 sts=4 et:
 use common::sense;
 
+use Scalar::Util qw{ openhandle };
+
 use File::Basename;
 use lib dirname(__FILE__) . '/../../../lib/perl';
 use OVH::Result;
@@ -48,7 +50,8 @@ osh_info "Use 'exit', 'quit' or ^D to stop.";
 osh_info "--- waiting for input";
 
 my @ret;
-while (my $line = <STDIN>) {
+my $line;
+while ((openhandle(\*STDIN)) && ($line = <STDIN>)) {
     chomp $line;
     last if (lc($line) eq 'exit' || lc($line) eq 'quit');