Probably the easiest way to get the Shepherd is with Guix, where it is used as the system service manager (PID 1) on Guix System and as the user service manager in Guix Home. But hey, you can also get its source code and run it on other systems!
Releases
Download source code releases from ftp.gnu.org.
Release announcements for the Shepherd are sent to the info-gnu mailing list (archive).
Occasionally, release candidates and test releases are published at alpha.gnu.org — use at your own risks!
Version control repository
Get the Shepherd fresh from Git with:
git clone https://git.savannah.gnu.org/git/shepherd.git
Check out the development page for more info.
Ready?
Check out the manual to get started!
Licensing
The Shepherd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 3 or any later version.