Q:

Replacing second same character in line

As you can probably see, I'm new here.
I've been searching for an answer to my question for an hour (yes, long time for this easy question) but I cannot find it.
The example of what I have (these are text files with few lines of text, but I've got a bunch of files):
G:072
O:2 
125/5 
K:201-5165/1988 
K:201-5165-1988

So what I would like it to look like:
G:072
O:2
125/5
K:201-5165/1988
K:201-5165/1988

I found a regex to find the second '-' in line but it doesn't work properly.
I use:^(K[^-]*)-([^-]*)-(.*$)
What I wanted it to do was to change - into /, but only the second -.
Instead of looking for only lines like K:201-5165-1988, it stops at first line with K, which already has the / K:201-5165/1988.
What do I do wrong? Why doesn't it look only for lines specified in regex?

A:

Ctrl+H
Find what: ^.+-.+\K-
Replace with: /
check Wrap around
check Regular expression
DO NOT CHECK . matches newline
Replace all

Explanation:
^           : beginning of line
  .+        : 1 or more any character
  -         : a dash
  .+        : : 1 or more any character
  \K        : forget all we have seen until this position
  -         : a dash

