One of the cute things you can do with
command.com is to
hexedit the strings for the command names to something else. Then create a
.BAT file with the same name as the command.
Example:
Command.com: dir --> fff
dir.bat:
@echo off
rem ph33r my m@d sk177z!!!!!!!!
fff %1 %2 %3 %4 %5 %6 %7 %8 %9 /a-h
Now
DIR won't list hidden files (including your hidden dir.bat). The
script kiddie potential is marvelous (similarly, editing
io.sys to change autoexec.bat and config.sys to differently named, hidden files)...
This was, of course, much more useful back in the days of dos 3.30, before programs like file manager made it easy to see what was going on.
To replace all instances of e with 3, so you can be a h4x0r, you could probably use ANSI.SYS to remap the screen, but that would do every text-mode program. (Which is probably all the more 1337).
And command.com won't run a dir.bat before dir builtin, even if it is in the %path%. It will, however, run an attrib.bat before attrib.exe, if attrib.bat is further ahead in the path.
Finally, there is a shell for linux called sash (stand alone shell) that has builtins for ls, mv, etc. just like command.com