Question: I have multiple snippets of C code similar to

```
const stFunctions m_fun = {
    NULL,

    &fun_1,
    &fun_2,

    NULL,

    &fun_3
};

```

I am trying to replace all `NULL,` using the `NULL,\n\n` regular expression in Notepad++ but it doesn't seem to work. I tried `NULL,` and `\n\n` and they both work.

Answer: 
You should be very careful when modifying source code with a regex. If you are sure that you want to remove whole lines with just `NULL,` in them and an empty line below that line, you may use

```
^\h*NULL,\h*\R{2}

```

The regex matches

* `^` - start of a line
* `\h*` - 0+ horizontal whitespaces
* `NULL,` - a `NULL,` string
* `\h*` - 0+ horizontal whitespaces
* `\R{2}` - 2 line breaks.
Don’t use regex!

The characters you’re searching for do not require regex. Select “extended characters” and search for `NULL,\r\n` (Windows) or `NULL,\n` (\*nix) and replace with whatever you want to replace it with.