vche is a hex editor and viewer which lets you see all the 256 characters (as found in video ROM), it somewhat resem bles old DOS programs.
It uses the /dev/vcs[1-63] and /dev/vcsa[0-63] character devices to do all it's screen I/O. So this program will run only on Linux on a local console, and not in X or remote sessions. There is a curses-variant vche-nc.
This program only runs in a system console!