I don't know if it's any better or worse than using a new filehandle, but it keeps me happy.

It's exactly as the same IMHO and in both ways it keeps me unhappy: I find your way to do what you want to do clumsy and error prone, which is probably the reason why I couldn't understand your question at all, first.

BTW: What would I do on a non-posix system?

But seriously, why don't you use <>'s magic instead?

q:~/tmp [22:37:14]$ cat headybrew.pl
#!/usr/bin/perl

chomp(my @msg =<>);
print @msg, "\n";

print "What do you want to do with this message?";

$response = <STDIN>;
print $response;

q:~/tmp [22:37:17]$ ./headybrew.pl 'ls|'
headybrew.plheadybrew.pl~
What do you want to do with this message?foo
foo
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