How to find-replace leading newlines in Cursor

I had a bunch of files with empty newlines at the start of the documents. I tried searching for these in Cursor (this should also work for VSCode) using \A to match at the absolute beginning of the file, but VSCode considered that invalid syntax. So I had to use negative-look-behind instead:

(?<![\s\S])(?:\r?\n)+

• (?<![\s\S]) = “there are no characters of any kind before me”
  • ?<! is the negative look-behind
  • \s\S means "whitespace or non-whitespace", i.e. any character
• (?:\r?\n)+ = the leading blank lines
  • (?: starts the non-capturing group
  • then match one or more blank new-lines

Similarly, to delete one or more empty lines at the end of files, you can use:

(\r?\n)(?:\r?\n)+$

...where $ means the very end of the file.