Software Tools, by Brian Kernighan and P.J.Plauger, Addison-Wesley, 1976, is an older book which showed the reader step by step how to build a UNIX-like environment on any system that supported a decent Fortran compiler, including almost all the source you needed. By the time you finished all the exercises, you had Ratfor, roff, m4, ed, grep, and other tools... the core of the UNIX command-line environment.
The tools were portable, and implemented a virtual file system on top of a native file system that allowed the Unix-like system to run on everything from CP/M-80 to Cray systems.
A few years later, Software Tools in Pascal was released, achieving the same goal for the next language to be popular.
RS made his first steps in C with Jim E. Hendrix's "Small C", which contained a suite of tools modeled closely after Kernighan/Plaugher, on a Z80+ machine. I was most amazed by the simplicity that most tools read from stdin, wrote to stdout, so they could be easily coupled into pipes.
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