Unix Philosophy - keshavbaweja-git/guides GitHub Wiki

Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new "features".
Expect the output of each program to become input to another, as yet unknown, program. Don't clutter output with extraneous information. Avoid stringently columnar or binary input formats. Don't insist on interactive input.
Design and build software, even operating systems, to be tried early, ideally within weeks. Don't hesitate to throw away clumsy parts and rebuild them.
Use tools in preference to unskilled help to lighten a programming task, even if you have to detour to build the tools and expect to throw some of them out after you've finished using them.