Special characters in Vim

Particularly when editing documents for human consumption rather than code, it’s often necessary to enter special characters into a document that can’t otherwise be produced by a single key press:

  • Letters with diacritical marks like ä, é, and ô — Vim refers to these as digraphs — a particular problem when using a US keyboard layout
  • Unicode characters like typographic dashes or copyright symbols ©, or other symbols from the multi-byte portion of the UTF-8 character set (including foreign languages)
  • Literal control characters like <Tab>

Vim has a method for inserting each of these within the editor, rather than having to copy-paste them from another document. We won’t discuss Vim’s alternative multibyte input methods here, and will assume that you’re using a keyboard with a US or UK layout, and predominantly type in English — apologies to international readers, but I do not have another type of keyboard to test this out!

Some of the following assumes that you’re using Vim in a UTF-8 capable terminal, and with the encoding option in your .vimrc set to utf-8, which is highly recommended for the vast majority of editing requirements:

set encoding=utf-8

It also assumes that your font is capable of displaying all of the characters concerned; monospace fonts with workable symbol coverage include Consolas, Inconsolata, and Ubuntu Mono.


Vim has a special shorthand for entering characters with diacritical marks. If you need some familiar variant of a Latin alphabet character with a diacritical mark or embellishment, it’s likely you’ll be able to input it with the digraph system. It also has support for some other sometimes-needed characters like thorn Þ and eszett ß, and Cyrillic characters.

Digraph input is started in insert or command mode (but not normal mode) by pressing Ctrl-k, then two printable characters in succession; the first is often the “base” form of the letter, and the second denotes the appropriate embellishment.

Some simple examples that might occasionally be needed for English speakers to correctly type one of the language’s many “loan words”:

  • Ctrl-k c , -> ç
  • Ctrl-k e ' -> é
  • Ctrl-k o ^ -> ô
  • Ctrl-k a ! -> à
  • Ctrl-k u : -> ü
  • Ctrl-k = e ->

This is just a small sample; Vim has support for a great many digraphs. Take a look at the relevant section of the documentation for a complete treatment of the feature. You can also type :digraphs within Vim to get a complete list of digraphs — several screenfuls of them!

Note that you can enter all of these characters using the Unicode mode discussed later in this article as well; two-character mnemonic digraphs simply happen to be easier to remember than four-digit codes.

Unicode characters

For characters not covered in the digraph set, you can also enter unicode characters by referring to their code page number. In insert or command mode (but not normal mode) this is done by typing Ctrl-v and then u, followed by the hexadecimal number. Some potentially useful examples:

  • Ctrl-v u 2018 -> , a LEFT SINGLE QUOTATION MARK
  • Ctrl-v u 2019 -> , a RIGHT SINGLE QUOTATION MARK
  • Ctrl-v u 2014 -> , an EM DASH
  • Ctrl-v u 00a9 -> ©, a COPYRIGHT SIGN

These are handy in some cases when writing HTML documents, as an alternative to using HTML entities like &mdash; or &copy;. An exhaustive summary of these characters and their codes is available on the Unicode website.

Other non-printable characters

The unicode character input method is actually a specialised case of inputting literal characters with a Ctrl-v prefix. We can input other non-printable and control characters using this prefix:

  • Ctrl-v <Enter> -> ^M
  • Ctrl-v <Tab> -> ^I

This is sometimes handy when conforming to someone else’s tab style, and can also be handy when searching for characters literally in searches.

Sync tmux panes

If you have a Tmux window divided into panes, you can use the synchronize-panes window option to send each pane the same keyboard input simultaneously:

Synchronize panes demo

You can do this by switching to the appropriate window, typing your Tmux prefix (commonly Ctrl-B or Ctrl-A) and then a colon to bring up a Tmux command line, and typing:

:setw synchronize-panes

You can optionally add on or off to specify which state you want; otherwise the option is simply toggled. This option is specific to one window, so it won’t change the way your other sessions or windows operate. When you’re done, toggle it off again by repeating the command.

This is an easy way to run interactive commands on multiple machines, perhaps to compare their speed or output, or if they have a similar setup a quick and dirty way to perform the same administrative tasks in parallel. It’s generally better practice to use Capistrano or Puppet for the latter.

Vi mode in Bash

Because the Bash shell uses GNU Readline, you’re able to set options in .bashrc and .inputrc to extensively customise how you enter your command lines, including specifying whether you want the default Emacs-like keybindings (e.g. Ctrl+W to erase a word), or bindings using a modal interface familiar to vi users.

To use vi mode in Bash and any other tool that uses GNU Readline, such as the MySQL command line, you need only put this into your .inputrc file, then log out and in again:

set editing-mode vi

If you only want to use this mode in Bash, an alternative is to use the following in your .bashrc, again with a login/logout or resourcing of the file:

set -o vi

You can check this has applied correctly with the following, which will spit out a list of the currently available bindings for a set of fixed possible actions for text:

$ bind -P

The other possible value for editing-mode is emacs. Both options simply change settings in the output of bind -P above.

This done, you should find that you open a command line in insert mode, but when you press Escape or Ctrl+[, you will enter an emulation of Vi’s normal mode. Enter will run the command in its present state while in either mode. The bindings of most use in this mode are the classic keys for moving to positions on a line:

  • ^ — Move to start of line
  • $ — Move to end of line
  • b — Move back a word
  • w — Move forward a word
  • e — Move to the end of the next word

Deleting, yanking, and pasting all work too. Also note that k and j in normal mode allow you to iterate through your history in the same way that Ctrl+P and Ctrl+N do in Emacs mode. Searching with ? and / doesn’t work by default, but the Ctrl+R and Ctrl+S bindings still seem to work.

If you are reasonably used to working with the modeless Emacs for most of your shell work but do occasionally find yourself in a situation where being able to edit a long command line in vi would be handy, you may prefer to press Ctrl+X Ctrl+E to bring up the command line in your $EDITOR instead, affording you the complete power of Vim to edit rather than the somewhat sparse vi emulation provided by Readline. If you want to edit a command you just submitted, the fc (fix command) Bash builtin works too.

The shell is a very different environment for editing text, being inherently interactive and fixed to one line rather than a static multi-line buffer, which leads some otherwise diehard vi users such as myself to prefer the Emacs mode for editing commands. For one thing, vi mode in Bash trips on the vi anti-pattern of putting you in insert mode by default, and at the start of every command line. But if the basic vi commands are etched indelibly into your memory and have become automatic, you may appreciate being able to edit your command line using these keys instead. It’s certainly worth a try at any rate, and I do still occasionally see set -o vi in the .bashrc files of a few of the pros on GitHub.

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