How can I add an ex-mode mapping in Vim?

Question

I've just created a Vim function to replace Windows linebreaks with Unix ones. Now I want to be able to type :linebreak and have it run. Here's my first attempt:

function UseUnixLineBreaks()
  :%s/^M/\r/g
endfunction

cmap linebreak :call UseUnixLineBreaks()<CR>

(By the way, that ^M is a control character - type it with Ctrl+v Ctrl+m)

When I try to run this by typing :linebreak, it does run, but it behaves oddly: each letter of the command appears in sequence, erasing the previous one. For example, I see :l, then :i, then :n, etc. When I type the last letter, it runs immediately.

I want the whole command to appear, so that I can see I've typed it correctly, then press enter to run it.

How can I do this?

Answer 1

Figured it out

Apparently what I want is not a mapping at all, but a command. So, the last line should be replaced with:

command Linebreak call UseUnixLineBreaks()

Note the capital "L" - user-defined commands must begin with a capital letter. See :help command.

Answer 2

That's how mappings work: the replacement takes place after the entire mapping is entered.

To create command aliases, try the cmdalias.vim script.

On a related note, :setl ff=unix.