On 3/25/2019 5:38 AM, mick crane wrote: > Is there any text editor, preferably in a terminal that has the facility > to protect lines in the document, not the document itself ? > I've got 2 blocks of "code" that look similar and I keep editing the > wrong one and then it doesn't work. Not strictly an answer but I would track the good file for example in Git. That way, you can always return back to a working state. $ git checkout -- . -- John Doe