[rbanffy]

For a lot of 8-bit computers, BASIC was the default operating system shell.

[gilcot]

Not exactly BASIC per se, there was some CP/M like additions. However, you're right 'cause some of those commands are BASIC extension (e.g. RUN can be used from your programme, LIST maybe, but CATalog/DIRectory or LOAD often not.) Old good time.