How can I pass a text to an external program without changing the current buffer?

Question

I want to do filter through an external program without actually filtering the lines (but to keep them). For example :

%!grep aa > newfile

If I do this, all the lines are deleted and I need to do undo

There is a more neat way to run an external program with args without changing the current buffer?

Thanks.

Answer 1

I think you’re looking for :help :write_c. Try this:

:w !grep aa > newfile

Answer 2

@Rich answered your question very well. However, judging by your example you may want to look into :vimgrep/:grep.

:vimgrep /pat/ %
:grep 'pat' %

Both :vimgrep & :grep will put the results into the quickfix list. Here are a few quickfix list commands to get you up and running fast:

• Use :cnext and :cprev to move between your errors/matches. I suggest you map these commands.
• :cfirst and :clast to go to the first and last error/matches respectively.
• :copen to open up the quickfix list in a window (:cclose to close)
• :cwindow to open quickfix list window only if there are errors
• :cc to display the current error/match.
• Use :cdo {cmd} to run a command, {cmd} on each quickfix entry.
• You can use % on the command-line to supply the current filename.

Vimcast episodes:

See the following Vimcasts episode:

• Project-wide find and replace Note: :cdo is available in Vim 8.
• Search multiple files with :vimgrep

For more help see the following:

:h quickfix
:h :cnext
:h :cfirst
:h :cope
:h :cwindow
:h :cc
:h :cdo
:h :_%