created 2002 · complexity basic · author tarjei · version 5.7
The ex command
g is very useful for acting on lines that match a pattern. You can use it with the
d command, to delete all lines that contain a particular pattern, or all lines that do not contain a pattern.
For example, to delete all lines containing "profile" (remove the
/d to show the lines that the command will delete):
More complex patterns can be used, such as deleting all lines that are empty or that contain only whitespace:
To delete all lines that do not contain a pattern, use
g!, like this command to delete all lines that are not comment lines in a Vim script:
g! is equivalent to
v, so you could also do the above with:
The next example shows use of
\| ("or") to delete all lines except those that contain "
error" or "
warn" or "
fail" (:help pattern):
- Remove unwanted empty lines
- Filter buffer on a search result
- Folding with Regular Expression
- Power of g
Can we delete/not delete the line that precedes the search string?
like, in the below example i want the command to search for "keyword" and then ratain that and the line before that and deletes the test? Thank you!
<< file starts>>
this is the line that preceeds the search string
<< file ends>>
- Easy, supply a Range to the
:g/keyword/-1d. --Fritzophrenic (talk) 22:09, May 20, 2015 (UTC)
Can we remove all even numbered lines in a file using this feature. can we do some kind of math in the pattern. (ex: \=line(".") % 2)
Not really, but you can do that in two steps:
:g/.*/if line('.')%2|call setline(line('.'), '===delete===')|endif :g/^==delete==$/d
If you simply put delete inside the if statement all the lines will be deleted. Much faster solution is to record a macro "ddj" and play it over the file. You could delete lines from several different ranges:
:let range = range(10,15)+range(20,25)+range(30,35) :g/.*/if index(range, line('.')) != -1|call setline(line('.'), '===delete===')|endif :g/^===delete===$/d
But again I think the faster way to do that is to use :[range]d several times.
How would you instead of deleting, replace matched lines with a single newline between remaining lines?
Use s/// instead. Make sure your pattern matches the whole line (by using wildcards and/or anchors), and replace it with nothing: