Match the beginning of a file in a VSCode regex search

Question

I'm trying to match the beginning of a file in a VSCode regex search to find and remove the following pattern:

//
Anything else to leave in place
etc.

I'd like to remove the first line in all files that contain //\n as the first characters. However when I perform a regex search for //\n it matches all occurences in all files obviously, regardless of their position in the file.

The regex language mentions the existence of \A to match the beginning of a line, or file in some editors, but VSCode rejects this regex as invalid: \A//\n.

So my question is, how can I match the beginning of a file in VSCode to achieve what I need?

Answer 1

The beginning of a file in Visual Studio Code regex can be matched with

^(?<!\n)
^(?<![\w\W])
^(?<![\s\S\r])

You may use

Find What: ^//\n([\s\S\r]*)
Replace With: $1

Or, since nowadays VSCode supports lookbehinds as modern JS ECMAScript 2018+ compatible environments, you may also use

Find What: ^(?<![\s\S\r])//\n
Replace With: empty

If you wonder why [\s\S\r] is used and not [\s\S], please refer to Multi-line regular expressions in Visual Studio Code.

Details

• ^ - start of a line
• // - a // substring
• \n - a line break
• ([\s\S\r]*) - Group 1 ($1): any 0 or more chars as many as possible up to the file end.

The ^(?<![\s\S\r])//\n regex means:

• ^(?<![\s\S\r]) - match the start of the first line only as ^ matches start of a line and (?<![\s\S\r]) negative lookbehind fails the match if there is any 1 char immediately to the left of the current location
• //\n - // and a line break.