Tor is a toolset for a wide range of organizations and people that want
to improve their safety and security on the Internet. Using Tor can help
you anonymize web browsing and publishing, instant messaging, IRC,
SSH, and other applications that use the TCP protocol. Tor also
provides a platform on which software developers can build new
applications with built-in anonymity, safety, and privacy features.

This script requires a 'tor' user/group to exist before running.
The recommended UID/GID is 220. You can create these like so:
  groupadd -g 220 tor
  useradd -u 220 -g 220 -c "The Onion Router" -d /dev/null -s /bin/false tor

You can pass another user/group to the script, this is however, less safe:
  TOR_USER=nobody TOR_GROUP=nogroup sh tor.SlackBuild

The following can be used to start/stop tor automatically:
/etc/rc.d/rc.local
 if [ -x /etc/rc.d/rc.tor ]; then
   /etc/rc.d/rc.tor start
 fi

/etc/rc.d/rc.local_shutdown
 if [ -x /etc/rc.d/rc.tor ]; then
   /etc/rc.d/rc.tor stop
 fi

Tor requires the libevent library, available from SlackBuilds.org.