text: Tabulators in Vim - Krzysztof Adamski
  Date Mon 24 June 2013 Tags vim
  Vim beginners tend to have some problems operating with tabulators and other non-printable characters. Here's a quick tour on available options.
  Showing non-printable characters
  In Vim, you can toggle showing non-printable characters on and off using set list!. Characters used to represent non-printable characters are not too pretty by default in Vim. Fortunately you can change it using listchars option. Here's the value that I like to use:
  set listchars=tab:▸\ ,eol:¬,nbsp:␣,trail:·
  In order to enter those strange characters in Vim, you can use ctrl-vuXXXX (changing XXXX to unicode hexadecimal code) while in insert mode. Here are the codes for the characters I use:
  ␣ - ctrl-vu2423
  · - ctrl-vu00b7
  ▸ - ctrl-vu25b8
  ¬ - ctrl-vu00ac
  If you only want to see one characters code, you can use ga command. It will show you the code of the character the cursor is on. It will work on both printable and non-printable characters.
  Expanding tabs to spaces
  If you want to use spaces instead of tabulator characters (like I do), set expandtab option. If this option is set, Vim will use appropriate number of spaces each time you try to insert tabulator character (note that even though pressing will move your cursor my multiple spaces, using will only delete one character by default). To disable this feature, set noexpandtab option.
  If you want to force Vim to insert tabulator character even if expandtab is set (and not replace it with spaces), you can use ctrl-v<TAB> command while in insert mode. This can be useful in Makefiles, for example.
  Tabulator width
  Vim uses 4 different options to control how tabulators are handled. I already mentioned expandtab boolean option. tabstop option specifies how many spaces tabulator character counts for, by default it's 8. This means that each tabulator will be separated by another by 8 spaces.
  shiftwidth is applied when < and > normal mode commands are used and it specifies how many spaces should be inserted at the beginning of the line. If noexpandtab is set, Vim will try to use tabs instead of spaces each time indentation can be represented with them. If it's not possible, it will mix tabs and spaces to ensure proper shift. To ensure consistency, you generally should set shiftwidth to be equal tabstop.
  softtabstop, the last option, is disabled (set to 0) by default. You can enable it by setting number of spaces that Vim uses each time you enter (or remove) tabulator character in insert mode. It's similar to shiftwidth in that Vim will try using tabulators if possible and noexpandtab. To ensure consistency, you generally should disable softtabstop or keep it equal to shiftwidth and tabstop. So why ever enabling softtabstop? For character. If it's set, in insert mode will delete the same number of characters that inserts.
  So my best advice is to always keep tabstop = shiftwidth = softtabstop. Wile it's possible to use any other combination in Vim, I can't imagine situation where this may be of much use.
  Converting tabs to spaces in whole file
  If you want to convert all tabulator characters to spaces with expandtab set, you can use :retab command. You can also use :retab! to change spaces back to tabs is your noexpandtab is on but you have to be careful with that when you are editing some code as this may brake your strings.
  Setting preferences according to filetype
  Some files requires you to use spaces instead of tabulators (like YAML) for example, while others forces tabulators (Makefiles). I already showed how to force inserting tab character even if expandtab is on but there's easier way - use different settings for different file types. To do this, use something like this in your vimrc file: