Question: I need to remove only the `LF`, not `CRLF`. Any idea about that? 

I can use PHP, notepad++, shell script, etc

![enter image description here](https://i.stack.imgur.com/0JUhH.png)

Answer: 
In notepad++

Try this : `(?<!\r)\n`

Make sure to set the option for regular expression in the search options, hope it helps
LF stands for line feed character, which is ASCII 10 or 0x0A or "\n" (in PHP). So just do 

`search_replace( "\n", '', $text)`

Pleae note CRLF are in fact two characters CR (carriage return) + LF. If you remove LF, you will still have CR (if any) in your text.

**EDIT**

If you want to remove just standalone LFs but keep CRLF then above code is wrong as it would turn CRLF into CRs. Use `preg_replace()` to do that

```
preg_replace("/(?<!\\r)\\n+(?!\\r)/", '', $text);

```

If for any reasons you'd like not to use `preg_replace()` (but do use it anyway), then you can try this dumb approach:

```
// save CRLFs by replacing with some text that does 
$tmp = str_replace("\r\n", 'S0m3L1k3LyUn1Qu3T3X7', $text);

// get rid of LFs
$tmp = str_replace("\n", '', $tmp );

// restore CRLFs
$text = str_replace('S0m3L1k3LyUn1Qu3T3X7', "\r\n", $tmp);

```