It's secure, stable, and (ugh) pretty.
At least DOS came with a Help program and I could learn the commands; Linux commands suck.
You're insane!
Almost all linux commands are programs, so if you want a list:
ls /bin
ls /usr/bin
ls /usr/local/bin
If you don't know what one of them does, try:
man <command>
info <command>
<command> --help
Generally, you'll get different levels of help from each of those. I'm not too familiar with "info", but I think you can type it on its own to get a big bad list of topics. Or, if you like man, you can do "man -K <search string>" to search all pages for that text.
If NONE of that is good enough, try
www.tldp.org or
www.linuxquestions.org or irc.prison.net #linuxhelp, they are all full of linux Gods who know everything there is to know.