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 any duplicates. I am interested in doing this from within vi/vim, if possible.

Answer 1

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

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

Answer 2

If you're OK with sorting your file, you can use:

:sort u

Answer 3

Select the lines in visual-line mode (shift-v), then :!uniq. That'll only catch duplicates which come one after another.

Answer 4

I would use !}uniq, but that only works if there are no blank lines. For every line in a file, :1,$!uniq

Answer 5

I would combine two of the answers above:

go to head of file
sort the whole file
remove duplicate entries with uniq

1G
!Gsort
1G
!Guniq

If you were interested in seeing how many duplicate lines were removed, use control-G before and after to check on the number of lines present in your buffer.

Answer 6

Regarding how Uniq can be implemented in VimL, search for Uniq in a plugin I'm maintaining. You'll see various ways to implement it that were given on Vim mailing-list.

Otherwise, :sort u is indeed the way to go.

Answer 7

g/^\(.*\)$\n\1/d

Works for me on Windows. Lines must be sorted first though.

Answer 8

http://vim.wikia.com/wiki/Uniq_-_Removing_duplicate_lines