Well, this is not a real screensaver. It's more a simple shell script to feed screensavers that can display text from a program, like Apple2, Phosphor or StarWars.
This shell scripts searches for files in a given directory, selects a random file and pipes it into the screensaver.
This is great to get reminded of your own code, to learn about new code or to show any arbitrary text file. Optionally you can specify a file name filter.
For example to show a *.c file from the linux sources specify this as program:
randomfile /usr/src/linux/ '*.c'
(NOTE: In this case the addtional / at the end is important since /usr/src/linux is a link on most distributions)