Substitution in Vim

See regex in vim for info on regex in Vim.

The :s (:substitute) command is used to substitute a pattern with a string. This is one of the most powerful and useful tools that you'll use in Vim.
wtf General syntax:

" For the current line 
:s/search/repl/flags
" For the visual selection 
:'<,'>s/search/repl/flags
" For the entire buffer 
:%s/search/repl/flags
" For the current line and all lines after it
:.,$s/search/repl/flags wtf
" For the current line and all lines before it 
:.,0s/search/repl/flags
" For the current line and 3 lines after it
:.,+3s/search/repl/flags

Regex Support

:s supports Basic Regular Expressions (BREs) by default (governed by the 'magic' option), and Extended Regular Expressions (EREs) with \v. E.g.,:

" Basic regular expression:
:s/\(capture_this\)/\1/g
" Extended regular expression:
:s/\v(capture_this)/\1/g

With \v, the parentheses don't need to be escaped in order to be treated as a capture group.

Substitute String

The second string in the :s command is the pattern to substitute.
This is called the "substitute string" in the docs.

:s/this is the search/this is the substitute string/

Special Characters in Substitutions

There are a few special characters that you can use in substitutions.
When used in a substitution (:s/)

• &: Keep the flags from the previous substitute.

  • Use in the flags to use the same flags as the last substitution.
    

    :s/foo/bar/gc
    " Use the same flags (gc):
    :s/foo/bar/& 
    

  • Use as a command (:&) to repeat the last substitution.
  • Use as a command with & (:&&) to repeat the last substitution, AND use the same flags.

• ~: The last string substituted.

  • E.g., If you switch out wow with cool, then ~ will be cool

    " foobar
    :s/foo/bar/
    " barbar
    :s/~/foo/
    " foobar
    

  • Use as a command (:~) to repeat the last substitution, but use the last search pattern.
  • Use as a command with & (:~&) to repeat the last substitution, but use the last search pattern AND use the same flags.

Special Character Examples

If I search for bar

/bar

Then I can use :~ to use foo instead of bar.

" Substitute 'foo' with 'bar' (by default it will use the last search pattern for replacement)
:s//bar/g foo
" Substitute 'bar' with 'foo'
:s/bar/~/g
" Substitute 'bar' with 'foo'
:s/~/foo/g

I can use ~ to use the last substitute pattern in a substitution.

" wowfoobar
:s/wow/foo/
" foofoobar
" Substitute 'bar' with 'foo'
:s/bar/~/g
" foofoofoo 

" Repeat the last substitution with the same pattern
:&
" Same as above, but also use the same flags
:&& 

" Repeat the last substitution, but with the last search pattern 
:~
" Same as above, but also use the same flags
:~&