I'm searching for a small linux distro for educational purposes. It should include:
1. All common tools: ls, cd, grep, date, env, who, mesg, mail, more... (dunno how they couldn't be included, but I'm a newbie, so just in case)
2. Vim and vimtutor
3. Bash

The following isn't needed:
1. GUI
2. Web tools (web browser, ppp etc.)

The following is unnecessary
1. Dev tools (gcc, gdb...)

One of the main characteristics for me is size. I wonder if my requirements can be met by a distro with download size < 10 mbytes. 10-50 mbytes are ok, but less size is better.

Thank you in advance and sorry for bad English

i'd suggest damnsmall which is a 50mb iso. if you go mugh smaller then you'll start losing things that *you* minght find essential but others would see as pointless. note that you can still easily install somethign like fedora and just only install a minimal system. you'd just need the large iso to start with.

you could run a busybox floppy disk, e.g. http://smsbr.sourceforge.net/SL/ which runs versions of most of those progarms as a single binary, which works in different ways depending on what you called it as. i'd expect somethign like this to be a little drastic for someone trying to learn about it.