#!/usr/bin/perl

sub catch_alarm { die "Timeout" }

for (;;) {
   eval {
        local $SIG{ALRM} = \&catch_alarm;
        undef $!;
        print "What do you want? >";
        alarm 10;
        if (defined( $line = readline STDIN )) {
           alarm 0;
           chomp $line;
           print "Here's some $line!\n";
        } elsif ($!) {
           die "Read error" ;
        }
    };
    if ( $@ =~ /Timeout/ ) {
           print "\nI grow tired of waiting!\n";
   }
}

What do you want? >foo
Here's some foo!
What do you want? >qlarch
Here's some qlarch!
What do you want? >
I grow tired of waiting!
What do you want? >