RE: Searching for commands by any part of command name

[Drew Adams]

> Attaching another question, why (I think) C-h a doesn't 
> display all the
> possible commands/variable/functions with a particular string inside,
> but just some of them?

C-h a is `apropos-command', which deals only with commands or, with `C-u', with
all functions (but not variables).

What you want is the command `apropos', which is not bound to a key by default:
`M-x apropos'. It is bound by default to menu item `Help > Search Documentation
> Find Any Object by Name'.