Keep running (don't exit after last line of code executes)

Hi. I'm trying to make a script that launches the server. I need it to launch within an Ant task (Ant is sort of non-problem for me, but Lisp is ) to run it along with my unit tests. What I fail to find, is how would I tell a Lisp program to not exit (when I say script I mean specifically SBCL invoked with --script argument). Ideally, I'd be happy to find some way to:
1. launch the script (or fasl) in a background process (think server.fasl -start & #server keeps running, but the script exits)
2. same script (whit another parameter), or another script that tells the server to stop.
I tried to find a simple setup for Hunchentoot or Webdav (this would probably fit well), but didn't find anything simple / good enough to even explain the process.

Think something like this:

<target ...>
    <exec name="shell-or-lisp-script" spawn="if-you-need?">
        <arg value="start-server"/>
    </exec>
    <junit .../><!-- a bunch of unit tests that talk to the server -->
    <exec name="shell-or-lisp-script" spawn="if-you-need?">
        <arg value="stop-server"/>
    </exec>
</target>

Thanks!

I have no experience with doing this, but you can use something like detachtty or screen to daemonize the SBCL process.

Thank you, this looks interesting (esp. detachtty)!
For now this is what I did (just in case anyone needs something quick to get things working in the time being).
start-server.lisp

;; This is some old-ish asdf function, I think it's called differently now
(asdf:oos 'asdf:load-op :video-rounds)
(rounds-web:start-server)
;; To keep us running. This looks like an ugly hack, 
;; but that's all I could find for now. 
(defvar alive t)
(loop (sleep 1000) (if (not alive) (quit)))

and then I have:
start

#!/bin/bash
nohup sbcl --script start-server.lisp > /dev/null 2> /dev/null &

and
stop

#!/bin/bash
PID=`ps aux | awk '/sbcl --script start-server.lisp$/ { print $2 }'`;
kill "$PID"

and then somewhere in my Ant script:

	<target name="start-hunchentoot"
		description="This is a test target. Don't use it yet. 
It's for launching web server for tests.">
		<exec executable="${SERVER_DIR}/start" dir="${SERVER_DIR}"/>
		<!--exec executable="${SERVER_DIR}/stop" dir="${SERVER_DIR}"/-->
	</target>

This isn't a production or long time support code. It's only for running unit tests, so I'm fine with it as it is, but, of course I'll try to find a cleaner way to do it.

I have an /etc/init.d/script that wraps around this and takes care of startup/shutdown at system boot/shutdown, but the code I use to kick off a hunchentoot server looks like this:

#!/bin/bash

# Starts up SBCL in a detached `screen` session, allowing you to
# reattach at will, so long as you log in as the same user as the one
# who owns this process.

# Might just need tweaking for other lisps. You never know...

# Notes:
# `screen -d -m` starts screen in "detached" mode

SCREEN=/usr/bin/screen

PACKAGE=$1
COMMAND=$2

# Limit the memory usage
# This helps prevent sbcl from taking over the entire machine.
MEMLIMIT=256

if [[ -z "$PACKAGE" || -z "$COMMAND" ]]
then
	echo "Need the package and at least one command as arguments!"
	exit 1
else
	$SCREEN -d -m sbcl --dynamic-space-size $MEMLIMIT --eval "(asdf:load-system $PACKAGE)" --eval "(in-package $PACKAGE)" --eval "($COMMAND)"
fi

This is used to load a package that handles running multiple webapps within a single hunchentoot instance, similar in spirit to Cyrus Harmon's hunchentoot-vhost package. It loads those systems, sets up the URL handlers, then starts Hunchentoot. I've been meaning to publish that for a while now, but it really needs porting to hunchentoot-1.1.1 first.

Thanks. Will have to read on /usr/bin/screen more. Didn't have to use it before / didn't even know such things exist.