macOS, also the latest version High Sierra, is even certified Unix [0]. Mac has non-standard hardware yes, bespoke software hell yes, but also pretty good stand

macOS, also the latest version High Sierra, is even certified Unix [0]. Mac has non-standard hardware yes, bespoke software hell yes, but also pretty good standard compliance when it comes to the lower level system interfaces - lower level as in below the various high level frameworks such as the UI toolkit Cocoa. The Linux Standard Base is a superset of POSIX (Portable Operating System Interface [for Unix]), with some small incompatibilities [1] [0] https://www.opengroup.org/openbrand/register/ https://www.opengroup.org/openbrand/register/ [1] ISO/IEC TR 24715:2006 Technical Report on the Conflicts between the ISO/IEC 9945 (POSIX) and the Linux Standard Base http://standards.iso.org/ittf/PubliclyAvailableStandards/ http://standards.iso.org/ittf/PubliclyAvailableStandards/ - there is probably a newer version of this report but that is not freely available