Removing duplicate rows in vi?

Question

I have a text file that contains a long list of entries (one on each line). Some of these are duplicates, and I would like to know if it is possible (and if so, how) to remove

Answer 1

Try this:

:%s/^\(.*\)\(\n\1\)\+$/\1/

It searches for any line immediately followed by one or more copies of itself, and replaces it with a single copy.

Make a copy of your file though before you try it. It's untested.