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created 2004 · complexity basic · author Yakov Lerner · version 6.0

On Unix-based systems, the Meta (Alt) key may not work in Vim. For example, in insert mode, pressing Meta-A (Alt-A) may exit to normal mode, then execute normal-mode commands. This can occur with non-GUI Vim under some terminal emulators – those which generate escape sequences for Meta-characters. The actually generated escape-sequences are <Esc>a .. <Esc>z.


You must manually configure Vim to recognize these escape-sequences as Meta-characters, see below. Terminal emulators which are known to generate these sequences for Meta-keys are: rxvt (unix), putty (PC), teraterm (PC). Vim expects characters 225-250 for Meta-keys.

Here's how to fix Meta-keys on the Vim side:

Check what your Meta-keys generate:

i<press Ctrl-V><press Meta-A>

If you see ^[a (that is, escape character followed by something), then add this snippet to your vimrc:

" fix meta-keys which generate <Esc>a .. <Esc>z
let c='a'
while c <= 'z'
  exec "set <M-".toupper(c).">=\e".c
  exec "imap \e".c." <M-".toupper(c).">"
  let c = nr2char(1+char2nr(c))

To fix Meta-keys definitions manually key-by-key:

:set <M-A>=<press Ctrl-V><press Meta-A>
:imap <press ctrl-v><press Esc>a <M-A>
; repeat each Meta-key.

Don't attempt to map <M-[> or <M-Leader> in this situation. The former will break mouse support (and possibly other things), and the latter doesn't play nicely when exiting insert mode and attempting to perform a leader-bound command.

See also[]


Suggested fix does not work in PuTTY on Windows XP, using Vim 6.1.5.

The Vim help files suggest, for example:

:set <M-b>=^[b

This works, but remember to set ttimeoutlen to something small!

Also note, Meta-key mappings are case-sensitive (e.g. <m-b> and <m-B> are different).

--Fritzophrenic 18:02, 30 June 2008 (UTC)

In rxvt I found that the :set <M-a>=^]a commands don't work, instead only the map commands are needed. So I used:

for i in range(65,90) + range(97,122)
  let c = nr2char(i)
  exec "map \e".c." <M-".c.">"
  exec "map! \e".c." <M-".c.">"

instead of the snippet given above, and everything works fine now.

Jzxu 12:20, 13 March 2009 (UTC)

^] is not ^[, chłopcze

Sean 5:09, 7 March 2021 (UTC)

With this mapping, after hitting ESC, you need to wait timeout(1000ms by default) before hitting any key. Otherwise you will stay in insert mode and input an escaped character.