Unix tools have endured for so long because they are simple, efficient, and composable. The Unix philosophy: 'Do one thing, and do it well.

_{find – 1971 / chmod – 1971 / ls – 1971
cd – 1971/ cp – 1971 / mv – 1971
rm – 1971 / cat – 1971 / echo – 1971
grep – 1973/ sed – 1974 / awk – 1977
sh – 1977 / tar – 1979}