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

awk '!x[$0]++' yourfile.txt if you want to preserve the order (i.e., sorting is not acceptable). In order to invoke it from vim, :! can be used.