:ab in out

Use in as abbreviation for out.

:unab in

Remove abbreviation for in.

:ab

List abbreviations.

:map c sequence

Map character c as sequence of commands.

:unmap c

Disable map for character c.

:map

List characters that are mapped.

:map! c sequence

Map character c to input mode sequence.

:unmap! c

Disable input mode map (you may need to quote the character with Ctrl-V).

:map!

List characters that are mapped to input mode.

qx

Record typed characters into register specified by letter x. If letter is uppercase, append to register.{vim}

q

Stop recording. {vim}

@x

Execute the register specified by letter x. {vim}