It is stated here that:
The Unix operating system introduced the idea of a toolkit. That is, rather than having a few generalized and complex utilities programs, the system contains a toolkit of small and simple programs which the user combines to perform sophisticated tasks and to create custom programs.
The author continues with an example where it mentions cut
, egrep
and wc
utilities.
So my question is:
"What requirements must a computer program meet to be considered as part to the unix toolkit?".
EDIT:
As stated in @Jesse_b's answer the POSIX standard defines a list of standard utilities. This list may change in the future. I would like to know what are the requirements that a utility must cope to be admited in such list.