Why is \r a newline for Vim?

Solution 1:

From http://vim.wikia.com/wiki/Search_and_replace :

When Searching

...

\n is newline, \r is CR (carriage return = Ctrl-M = ^M)

When Replacing

...

\r is newline, \n is a null byte (0x00).

Solution 2:

From vim docs on patterns:

\r matches <CR>

\n matches an end-of-line - When matching in a string instead of buffer text a literal newline character is matched.

Solution 3:

Another aspect to this is that \0, which is traditionally NULL, is taken in s//\0/ to mean "the whole matched pattern". (Which, by the way, is redundant with, and longer than, &).

So you can't use \0 to mean NULL, so you use \n
So you can't use \n to mean \n, so you use \r.
So you can't use \r to mean \r, but I don't know who would want to add that char on purpose.

—☈

Solution 4:

`:help NL-used-for-Nul`

Technical detail:

<Nul> characters in the file are stored as <NL> in memory. In the display they are shown as "^@". The translation is done when reading and writing files. To match a <Nul> with a search pattern you can just enter CTRL-@ or "CTRL-V 000". This is probably just what you expect. Internally the character is replaced with a <NL> in the search pattern. What is unusual is that typing CTRL-V CTRL-J also inserts a <NL>, thus also searches for a <Nul> in the file. {Vi cannot handle <Nul> characters in the file at all}

Solution 5:

First of all, open :h :s to see the section "4.2 Substitute" of documentation on "Change". Here's what the command accepts:

:[range]s[ubstitute]/{pattern}/{string}/[flags] [count]

Notice the description about pattern and string

For the {pattern} see |pattern|.
{string} can be a literal string, or something
special; see |sub-replace-special|.

So now you know that the search pattern and replacement patterns follow different rules. If you follow the link to |pattern|, it takes you to the section that explains the whole regexp patterns used in Vim.

Meanwhile, |sub-replace-special| takes you to the subsection of "4.2 Substitute", which contains the patterns for substitution, among which is \r for line break/split.

(The shortcut to this part of manual is :h :s%)