How to comment uncomment lines in vim?

To comment out one or more lines in Vim, you can use the : command followed by the s command and a search pattern. For example, to comment out all lines that contain the word “hello”, you can use the following command:

:s/hello/# hello/g

This will replace every occurrence of the word “hello” with # hello.

To uncomment a line or lines, you can use a similar command but replace the # with a space. For example, to uncomment all lines that contain the word “hello”, you can use the following command:

:s/# hello/hello/g

This will replace every occurrence of # hello with just “hello”.

You can also use the : command followed by the g command to comment out or uncomment multiple lines at once. For example, to comment out the current line and the two lines below it, you can use the following command:

:3,5s/^/#/

This will add a # character to the beginning of each line in the range 3,5.

To uncomment the same lines, you can use the following command:

:3,5s/^#//

This will remove the # character from the beginning of each line in the range 3,5.

Note that these commands may not work if the comment character for your programming language is something other than #. In that case, you will need to use the appropriate comment character in the search pattern.