Vim Notes
Categories:

To find the next line in a file that does not contain a string:

/^\%(\%(STRING\)\@!.\)*$

Join every other line in a file:

:%normal Jj

Delete every line in a file that contains a string:

:g/string/d

Delete lines in a file that contain this or that string:

:g/this\|that/d

Delete lines in a file that do not contain a string:

:g!/string/d