Find and replace n characters long random string in Notepad++ using wildcards/regex

Please make sure you have a backup in case something goes wrong.

• In Notepad++ go to Search → Replace
• In the Find What textbox paste the following: youtubehd:\w\w\w\w\w\w\w\w
• In the Replace With textbox paste the following: youtubehd
• Ensure that Search Mode is set to Regular expression
• Click Replace All

Thanks to KCotreau for pointing out that search mode defaults to Normal and needs to be changed.

Edit:

It's been pointed out in the comments below that you could instead use youtubehd:\w{8} as your search pattern. This is correct and indeed preferable. Support for this was only added in Notepad++ v6 though which came out after this was originally written hence the reason why I used the longer form. See here for more.