Setting Options

Vim has many options you can set to change how it behaves.

There are two main kinds of options: boolean options (either "on" or "off") and options that take a value.

Boolean Options

Run the following command:

:set number

Line numbers should appear on the left side of the window if they weren't there already. Now run this:

:set nonumber

The line numbers should disappear. number is a boolean option: it can be off or on. You turn it "on" by running :set number and "off" with :set nonumber.

All boolean options work this way. :set <name> turns the option on and :set no<name> turns it off.

Toggling Boolean Options

You can also "toggle" boolean options to set them to the opposite of whatever they are now. Run this:

:set number!

The line numbers should reappear. Now run it again:

:set number!

They should disappear once more. Adding a ! (exclamation point or "bang") to a boolean option toggles it.

Checking Options

You can ask Vim what an option is currently set to by using a ?. Run these commands and watch what happens after each:

:set number
:set number?
:set nonumber
:set number?

Notice how the first :set number? command displayed number while the second displayed nonumber.

Options with Values

Some options take a value instead of just being off or on. Run the following commands and watch what happens after each:

:set number
:set numberwidth=10
:set numberwidth=4
:set numberwidth?

The numberwidth option changes how wide the column containing line numbers will be. You can change non-boolean options with :set <name>=<value>, and check them the usual way (:set <name>?).

Try checking what a few other common options are set to:

:set wrap?
:set shiftround?
:set matchtime?

Setting Multiple Options at Once

Finally, you can specify more than one option in the same :set command to save on some typing. Try running this:

:set numberwidth=2
:set nonumber
:set number numberwidth=6

Notice how both options were set and took effect in the last command.

Exercises

Read :help 'number' (notice the quotes).

Read :help relativenumber.

Read :help numberwidth.

Read :help wrap.

Read :help shiftround.

Read :help matchtime.

Add a few lines to your ~/.vimrc file to set these options however you like.