Basic search and replaceEdit

The :substitute command searches for a text pattern, and replaces it with a text string. There are many options, but these are what you probably want:

:%s/foo/bar/g
Find each occurrence of 'foo', and replace it with 'bar'.
:%s/foo/bar/gc
Change each 'foo' to 'bar', but ask for confirmation first.
:%s/\<foo\>/bar/gc
Change only whole words exactly matching 'foo' to 'bar'; ask for confirmation.
:%s/foo/bar/gci
Change each 'foo' (case insensitive) to 'bar'; ask for confirmation.
:%s/foo/bar/gcI
Change each 'foo' (case sensitive) to 'bar'; ask for confirmation.

The g flag means global – each occurrence in the line is changed, rather than just the first.

DetailsEdit

Search range:

:s/foo/bar/g Change each 'foo' to 'bar' in the current line.
:%s/foo/bar/g Change each 'foo' to 'bar' in all lines.
:5,12s/foo/bar/g Change each 'foo' to 'bar' for all lines from line 5 to line 12 inclusive.
:'a,'bs/foo/bar/g Change each 'foo' to 'bar' for all lines from mark a to mark b inclusive.
:.,$s/foo/bar/g Change each 'foo' to 'bar' for all lines from the current line (.) to the last line ($) inclusive.
:.,+2s/foo/bar/g Change each 'foo' to 'bar' for the current line (.) and the two next lines (+2).
:%s/foo/bar/g Equivalent to :1,$s/foo/bar/g (change all lines).
:g/^baz/s/foo/bar/g Change each 'foo' to 'bar' in each line starting with 'baz'.

When searching:

., *, \, [, ], ^, and $ are metacharacters.
+, ?, |, {, }, (, and ) must be escaped to use their special function.
\/ is / (use backslash + forward slash to search for forward slash)
\t is tab, \s is whitespace
\n is newline, \r is CR (carriage return = Ctrl-M = ^M)
\{#\} is used for repetition. /foo.\{2\} will match foo and the two following characters. The \ is not required on the closing } so /foo.\{2} will do the same thing.
\(foo\) makes a backreference to foo. Parenthesis without escapes are literally matched. Here the \ is required for the closing \).

When replacing:

\r is newline, \n is a null byte (0x00).
\& is ampersand (& is the text that matches the search pattern).
\1 inserts the text of the first backreference. \2 inserts the second backreference, and so on.

You can use other delimiters with substitute:

:s#http://www.example.com/index.html#http://example.com/#

Save typing by using \zs and \ze to set the start and end of a pattern. For example, instead of:

:s/Copyright 2007 All Rights Reserved/Copyright 2008 All Rights Reserved/

Use:

:s/Copyright \zs2007\ze All Rights Reserved/2008/

Using the current word or registersEdit

:%s//bar/g
Replace each match of the last search pattern with 'bar'.
For example, you might first place the cursor on the word foo then press * to search for that word.
The above substitute would then change all words exactly matching 'foo' to 'bar'.
:%s/foo/<c-r><c-w>/g
Replace each occurrence of 'foo' with the word under the cursor.
<c-r><c-w> means that you press Ctrl-R then Ctrl-W.
The word under the cursor will be inserted as though you typed it.
:%s/foo/<c-r><c-a>/g
Replace each occurrence of 'foo' with the WORD under the cursor (delimited by whitespace).
<c-r><c-a> means that you press Ctrl-R then Ctrl-A.
The WORD under the cursor will be inserted as though you typed it.
:%s/foo/<c-r>a/g
Replace each occurrence of 'foo' with the contents of register 'a'.
<c-r>a means that you press Ctrl-R then a.
The contents of register 'a' will be inserted as though you typed it.
:%s/foo/\=@a/g
Replace each occurrence of 'foo' with the contents of register 'a'.
\=@a is a reference to register 'a'.
The contents of register 'a' is not shown in the command. This is useful if the register contains many lines of text.
:%s//<c-r>//g
Replace each match of the last search pattern with the / register (the last search pattern).
After pressing Ctrl-R then / to insert the last search pattern (and before pressing Enter to perform the command), you could edit the text to make any required change.
:%s/<c-r>*/bar/g
Replace all occurrences of the text in the system clipboard (in the * register) with 'bar' (see next example if multiline).
On some systems, selecting text (in Vim or another application) is all that is required to place that text in the * register.
:%s/<c-r>a/bar/g
Replace all occurrences of the text in register 'a' with 'bar'.
<c-r>a means that you press Ctrl-R then a. The contents of register 'a' will be inserted as though you typed it.
Any newlines in register 'a' are inserted as ^M and are not found.
The search works if each ^M is manually replaced with '\n' (two characters: backslash, 'n').
This replacement can be performed while you type the command:
:%s/<c-r>=substitute(@a,"\n",'\\n','g')<CR>/bar/g
The "\n" (double quotes) represents the single character newline; the '\\n' (single quotes) represents two backslashes followed by 'n'.
The substitute() function is evaluated by the <c-r>= (Ctrl-R =) expression register; it replaces each newline with a single backslash followed by 'n'.
The <CR> indicates that you press Enter to finish the = expression.

See Paste registers in search or colon commands instead of using the clipboard.

Additional examplesEdit

:%s/foo/bar/
On each line, replace the first occurrence of "foo" with "bar".
:%s/.*\zsfoo/bar/
On each line, replace the last occurrence of "foo" with "bar".
:%s/\<foo\>.*//
On each line, delete the whole word "foo" and all following text (to end of line).
:%s/\<foo\>.\{5}//
On each line, delete the whole word "foo" and the following five characters.
:%s/\<foo\>\zs.*//
On each line, delete all text following the whole word "foo" (to end of line).
:%s/.*\<foo\>//
On each line, delete the whole word "foo" and all preceding text (from beginning of line).
:%s/.*\ze\<foo\>//
On each line, delete all the text preceding the whole word "foo" (from beginning of line).
:%s/.*\(\<foo\>\).*/\1/
On each line, delete all the text preceding and following the whole word "foo".

Special casesEdit

For substituting patterns with a corresponding case-sensitive text, Michael Geddes's keepcase plugin can be used, e.g.:

:%SubstituteCase/\cHello/goodBye/g
Substitute 'Hello hello helLo HELLO' by 'Goodbye goodbye goodBye GOODBYE'

For changing the offsets in a patch file (line number of a block), this little snippet can be used:

s/^@@ -\(\d\+\),\(\d\+\) +\(\d\+\),\(\d\+\) @@$/\="@@ -".eval(submatch(1)+offsetdiff).",".submatch(2)." +".eval(submatch(3)+offsetdiff).",".submatch(4)." @@"/g

Useful when we want to strip some blocks from a patch, without patch having to complain about offset differences.

Note Should try to make the expression more compact, but don't know how without having the possibility of modifying unwanted lines.