#same initialization
my $pid = open2( \*Reader, \*Writer, "/bin/bash" ) or warn $!;
Writer->autoflush();
Reader->autoflush();
STDIN->autoflush();
$SIG{ALRM} = sub {die}; # required for alarm call below
do {
    print ": "; # simple prompt
    my $cmd = <STDIN>;
    print Writer $cmd;
    my $got;
    while (1) {
        eval { alarm 3; $_=<Reader> }; # get line in 3 seconds or stop reading
        alarm 0;
        last if ($@ or !(defined($_))); # exit loop if there was a timeout or no data
        $got .= $_;
    }
    print $got;
} while(1);