What is 66?

Sixty-six is a service manager providing init built around s6 created to make the implementation and manipulation of service files on your machine easier. It is meant to be a toolbox for the declaration, implementation and administration of services to achieve powerful functionality with small amounts of code.

Examples of what can be achieved by assembling different programs provided by 66:

66 can easily be used within container. With one command, 66 scandir start, you are ready to go to supervise and manage any kind of service as root or regular account.

Booting with 66 to be able to supervise and manage services is not mandatory. You can use it in parallel with another init or service manager, start a scandir directory with the 66 scandir start command, and you are ready to supervise any kind of services.

Note: This documentation tries to be complete and self-contained. However, if you have never heard of s6 you might be confused at first. Please refer to the skarnet documentation if in doubt.



Please refer to the file for details.


66 is free software. It is available under the ISC license.


See changes between version.

(!) The significant changes in versions and above render them incompatible with versions prior to You can refer to the Rosetta Stone to understand the interface and behavioral differences between versions below and version


Extra tools

Internal tools

Others documentation

Why is 66 necessary?

Implementation and handling of service files based on s6 can be complex and difficult to understand. This led to the creation of the 66 program.

Why the name?

Previously 66 was the result of the combination of the former s6 and s6-rc. With time and code improvement the s6-rc program was dropped. 66 is now a fully independent service manager, although the name has been retained. It is a lot faster and easier to write and remember when writing. Apart from that it is a nice command prefix to have. It identifies the origin of the software and it’s short.

Expect more use of the 66- prefix in future obarun software releases and please avoid using it for your own projects.