The term GNU's Not Unix is a legal ploy to include the word Unix in the name, thus implying some relationship, while explicitly disclaiming a relationship by the same, potentially avoiding claims of trademark infringement. Moreover, RMS and other of GNU's principal authors resent Unix due to their experience with Lisp and other systems which they believe to be technically superior, yet (as history has shown) significantly less marketable and apparently less practical for reasons that make no sense to hackers. Worse is better [L1 ]. Thus, GNU was born as a trampoline from which an operating system superior to Unix might one day be developed, yet naturally Unix must first be implemented in order for GNU to be adopted.
Tcl programmers should take note of two particular aspects of the GNU project:
gcc is called nowadays the GNU Compiler Collection, given the variety of front- and backends to the same internal engine.