Changes: Delete all lines containing a pattern

Revision as of 22:09, 20 May 2015

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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):

:g/profile/d

More complex patterns can be used, such as deleting all lines that are empty or that contain only whitespace:

:g/^\s*$/d

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!/^\s*"/d

Note that g! is equivalent to v, so you could also do the above with:

:v/^\s*"/d

The next example shows use of \| ("or") to delete all lines except those that contain "error" or "warn" or "fail" (:help pattern):

:v/error\|warn\|fail/d

Comments

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

keyword

asdfgf asdfgf

lkjhj lkjhj

<< file ends>>

Easy, supply a Range to the d command: :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?

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-The ex command, 'g' is very useful for acting on lines that match a pattern. You can use it with the ex command, 'd' to delete all lines that contain/do not contain a particular pattern.
+The ex command <code>g</code> is very useful for acting on lines that match a pattern. You can use it with the <code>d</code> command, to delete all lines that contain a particular pattern, or all lines that do not contain a pattern.
-For a trivial example, delete all lines containing "profile":
+For example, to delete all lines containing "profile" (remove the <code>/d</code> to show the lines that the command will delete):
 <pre>
 :g/profile/d
 </pre>
-Obviously, more complex patterns can be used, such as deleting all lines that are empty or contain only whitespace:
+More complex patterns can be used, such as deleting all lines that are empty or that contain only whitespace:
 <pre>
 :g/^\s*$/d
 </pre>
-Finally, to delete all lines that do NOT contain a pattern, use g!, like this command to delete all lines that are not comment lines in a Vim script:
+To delete all lines that do ''not'' contain a pattern, use <code>g!</code>, like this command to delete all lines that are not comment lines in a Vim script:
 <pre>
 :g!/^\s*"/d
 </pre>
-Note that the 'g!' command is equivalent to the 'v' command, so you could also do the above with:
+Note that <code>g!</code> is equivalent to <code>v</code>, so you could also do the above with:
 <pre>
 :v/^\s*"/d
+</pre>
+The next example shows use of <code>\|</code> ("or") to delete all lines ''except'' those that contain "<code>error</code>" or "<code>warn</code>" or "<code>fail</code>" ({{help|pattern}}):
+<pre>
+:v/error\|warn\|fail/d
 </pre>
 ==See also==
+*[[VimTip72|Remove unwanted empty lines]]
-*[[Filter buffer on a search result]]
+*[[VimTip1557|Filter buffer on a search result]]
-*[[Folding with Regular Expression]]
+*[[VimTip282|Folding with Regular Expression]]
+*[[VimTip227|Power of g]]
 ==Comments==
+Can we delete/not delete the line that precedes the search string?
+like, in the below example i want the command to search for "keyword" and then ratain that and the  line before that and deletes the test? Thank you!
+<< file starts>>
+this is the line that preceeds the search string
+keyword
+asdfgf asdfgf
+lkjhj lkjhj
+<< file ends>>
+:Easy, supply a [[Range]] to the <code>d</code> command: <code>:g/keyword/-1d</code>. --[[User:Fritzophrenic|Fritzophrenic]] ([[User talk:Fritzophrenic|talk]]) 22:09, May 20, 2015 (UTC)
+----
+Can we remove all even numbered lines in a file using this feature. can we do some kind of math in the pattern. (ex: \=line(".") % 2)
+Not really, but you can do that in two steps:
+<pre>
+:g/.*/if line('.')%2|call setline(line('.'), '===delete===')|endif
+:g/^==delete==$/d
+</pre>
+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:
+<pre>
+: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
+</pre>
+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?