Thursday, April 29, 2010

vim vs. grep : external quickfix/error file

My usual trick of using vim with grep works well when single grep invocation is sufficient.

Yet quite often I end up piping one grep's output to another grep to refine the results. And that doesn't work with my old trick of wrapping the grep MethodName *.cpp into vim -c ":grep MethodName *.cpp" as the vim's internal grep doesn't support pipes.

Digging through the documentation I found that it is possible to accomplish and it fits well to my workflow.

Start grepping(*):

$ grep MethodName *.cpp # not fine enough...
$ grep MethodName *.cpp | grep -v rubbish # much better
    # and save to a file
$ grep -n MethodName *.cpp | grep -v rubbish > tmp1.out

N.B. -n to the grep is required as VIM needs line numbers to jump to the locations.

And now tell VIM to use the produced tmp1.out error file:

$ vim -q tmp1.out


$ vim -c ":cf tmp1.out"

or from inside running VIM:

:cf tmp1.out

Check the :h :cf for the official documentation.

(*) Obviously in the case it doesn't have to be grep - anything what produces similar output would do. I used once a perl script to generate VIM-compatible error file from diff output to preview potential merge conflicts.

Friday, April 16, 2010

Capture output of a command

I was playing around with ^K and wanted to see all possible combinations available. :help CTRL-K directed to the :digraphs command. The problem is that amount of output from :dig eclipses even that of the :set all.

So how one can somehow serialize the output into e.g. a VIM's buffer?

Search on the net unveiled the following tip:

:redir @a
:redir END

Or even cooler, putting the output into a variable:

:redir => varname
:redir END

followed by echo varname.

Final step is the dumping all that into a buffer/window: :put =varname.

P.S. The official Learn to use help article. Til now, I haven't knew that the :help could be abbreviated to the :h.

Monday, April 12, 2010

Save file owned by root

Have just seen the nice trick on the Interwebs.

It happens often: one starts editing a file owned by root. One gets used rather quickly to the VIM's warnings about editing a file one does not have permissions to. Only much later realizing that you can't save it.

So you opened a VIM and edited a file, but can't save it. Instead of saving a temp one can use the trick:

:w !sudo tee %

P.S. ZOMG PONYZ!!1 For what I was always adding a custom shortcut :map <F6> :b#<CR> turned out to have an official shortcut: ^6 (:help CTRL-6). In VIM 7.1, this is sole shortcut of the form CTRL-<number>.