Regex: replace backslash with double-backslash, but not double-backslash with quadruple-backslash

Question

I have the following regex:

s/\\/\\\\/g

This does a nice job of replacing all "\" characters with "\\". However, I want to guard against matching backslashes that are adjacent to other backslashes. If I do this:

s/[^\\]\\[^\\]/\\\\/g

it only catches non-adjacent backslashes. But now there's the obvious problem that the matches include the two neighboring charaters that shouldn't be replaced. How can I overcome this?

Answer 1

If you know what escaped characters you want to match you can always just include all those cases (\n,\r,\t,\"....)

Answer 2

How about a negative lookahead to specify "replace this slash unless it is followed by another slash"?

Answer 3

s/([^\\])\\([^\\])/$1\\\\$2/g