Is it true that Brian Kernighan while developing
rm accidentally tested the project so that it removed itself? Then, according to story, he had to start over from the beginning because there was no backup. I heard the story from somebody but could not verify that it is true.
Brian Kernighan was involved with Unix since very early days, so it’s still possible, but he wouldn’t have been a primary developer on
rm. In any case
rm is simple enough, even in V7, that its deletion wouldn’t have been much of a loss; it wouldn’t have taken long to re-create.
As an aside, specifying
rm as a script’s shebang allows an executable to delete itself when executed (along with any file given as argument).