Enlightened Monks!

I'm trying to run a command that runs some kind of interactive shell, executes a script, and then stays in the shell. It's stubborn, and does not exit the shell, even if I explicitly provide an exit command in the script file. Also, it hangs frequently, so I cannot be sure that for a given script, I will receive any output (so I cannot use a solution that would open the command with a pipe, then read first X lines, then kill it).

Right now, I'm trying to adopt the idea found here: Re: killing command if it takes too much time. I want all the lines, so I modified it a bit. This is the code after my modifications, and the way I use this sub later:

 
sub cmd_wrapper {
    my $timeout = shift;
    my $cmd     = shift;
    
    my @out;    # all lines of output
    my $return_code;
    
    eval { 
        local $SIG{ALRM} = sub { die "alarm\n" };
        alarm $timeout;
        @out = (`$cmd`);
        $return_code = $?;
        alarm 0;
    };
    
    if( $@ ) {
        die "Eval failed for $cmd for unknown/unexpected reasons" if $
+@ ne "alarm\n"; 
        die "Eval failed for $cmd because alarm timed out";
    }
    die "Return code undefined for $cmd" unless defined $return_code;
    return $return_code, @out if wantarray;
    return $return_code;
}

@cmdoutput = cmd_wrapper(15, "my_stubborn_shell -c $filename"); # Will
+ timeout in 15 seconds
$cmd_ret_code = shift @cmdoutput;

[download]

This, however, does not work. It just times out with "Eval failed because alarm timed out". How can I gather the output, and then kill the program, after a given time (let's say, 20 seconds)?

I could always do it with Expect (especially since I can exit the shell without problems when in interactive mode), but maybe there is an easier solution. If Expect is the right way to do this, please, let me know.

regards,
Luke Jefferson