Honestly any interactive shell + unix tools + any scripting language you feel comfortable with should cover the majority of things you may want to do on the command line.
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.