Remember that echo.c evolved long before UNIX has shared libraries. So avoiding stdio completely might mean the size of your binary drops from 50K to 5K. If y

Remember that echo.c evolved long before UNIX has shared libraries. So avoiding stdio completely might mean the size of your binary drops from 50K to 5K. If you're on a PDP-11 with 256KB of RAM (being shared by several users) this would make a big difference. My earliest UNIX programming was in the mid-80s on a machine with a (luxurious!) 1.5MB of RAM. I definitely remember avoiding stdio when writing small utilities that I wanted to start up and run fast. Also remember that back in those days echo was not a shell builtin. (Hell, back then the testing operator '[' wasn't even a builtin. Some UNIXes like OS/X still have a vestigial /bin/[ executable!) Programs like echo that ran from shell scripts constantly had to be coded to start up as fast as possible.