Fix meta-keys that break out of Insert mode
From Vim Tips Wiki
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)) endw
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.
 See also
Suggested fix does not work in PuTTY on Windows XP, using Vim 6.1.5.
The Vim help files suggest, for example:
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.">" endfor
instead of the snippet given above, and everything works fine now.
Jzxu 12:20, 13 March 2009 (UTC)
- ^] is not ^[, chłopcze