• Was a OS in the 60s, 70s
  • Now it is mainly a UNIX Standards Compliant Licence - SUS


  • Stands for Single Unix Specification
  • A Similar standards to POSIX
  • Significant license fee associated with getting this branding, but certified means compatible with other Unix based system


  • macOS (after 2015)
  • Solaris (Oracle)


  • Unix-like operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the SUS
  • A Unix-like application is one that behaves like the corresponding Unix command or shell. Although there are general philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like