How to Put Newline Characters in Substitutions of Regular Expressions of GVim

I use GVim on Windows 7.

I want to learn how to put newline characters by using regex substitutions. To do this I try to use \r and \n metacharacters but the substituted text doesn't show normal newlines.

For example, at the beginning I have:

line 1
line 2

I use the following substitution expression:

:%s/\n/\n\n/g

Then GVim produces the following text:

line 1^@^@line 2^@^@

Instead, if I use \r\n in the substitution expression

:%s/\n/\r\n/g

Then GVim produces the following text:

line 1
^@line 2
^@

What are those ^@ characte开发者_Python百科rs?

How to use newline characters in the substitution expression properly?

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^@ is a nul

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For some reason, vim wants to see \r in the replacement text in order to insert a newline. (\n in the replacement inserts a nul.)

So, after succesfully locating newlines by running /\n, try:

s//\r/

Or to add an extra newline:

s/$/\r/

On the pattern side, \r means an actual (015) CR character, leading to the following strange-looking command when you want to replace returns with newlines:

s/\r/\r/

No, it's not a no-op.

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This

s/\r/\r/

fails. But

s/\n/\r/

works fine.