How to make the tab character 4 spaces instead of 8 spaces in nano?

176
votes

When I press TAB in nano editor, the cursor will jump with 8 spaces like this:

def square(x):
        return x * x
def cube(y):
        return y * y * y

how can I set the tab stop width to 4 spaces to display like this:

def square(x):
    return x * x
def cube(y):
    return y * y * y
6
tabsterminalindentationnano
Nano is a pretty basic editor. There's a good chance it just doesn't support this. - millimoose
umm not only in nano, but it also indent by 8 spaces when I use python interpreter in Terminal. - Fallen Satan
This is answered on SuperUser, and should be closed as duplicate: superuser.com/questions/110421/tab-character-width-in-terminal - millimoose
@millimoose, changing the tab stops in the terminal doesn't affect nano. This question should be specifically about nano or about setting the tab stops for Python, but not about both and not about interactively setting the tab stops with the tab command, which doesn't affect all programs. - Chris Page

6 Answers

281
votes

If you use nano with a language like python (as in your example) it's also a good idea to convert tabs to spaces.

Edit your ~/.nanorc file (or create it) and add:

set tabsize 4
set tabstospaces

If you already got a file with tabs and want to convert them to spaces i recommend the expandcommand (shell):

expand -4 input.py > output.py
104
votes

Command-line flag

From man nano:

-T cols (--tabsize=cols)
    Set the size (width) of a tab to cols columns.
    The value of cols must be greater than 0. The default value is 8.
-E (--tabstospaces)
    Convert typed tabs to spaces.

For example, to set the tab size to 4, replace tabs with spaces, and edit the file "foo.txt", you would run the command:

nano -ET4 foo.txt

Config file

From man nanorc:

set tabsize n
    Use a tab size of n columns. The value of n must be greater than 0.
    The default value is 8.
set/unset tabstospaces
    Convert typed tabs to spaces.

Edit your ~/.nanorc file (create it if it does not exist), and add those commands to it. For example:

set tabsize 4
set tabstospaces

Nano will use these settings by default whenever it is launched, but command-line flags will override them.

12
votes

In nano 2.2.6 the line in ~/.nanorc to do this seems to be

set tabsize 4

Setting tabspace gave me the error: 'Unknown flag "tabspace"'

4
votes

For future viewers, there is a line in my /etc/nanorc file close to line 153 that says "set tabsize 8". The word might need to be tabsize instead of tabspace. After I replaced 8 with 4 and uncommented the line, it solved my problem.

1
votes

For anyone who may stumble across this old question ...

There is one thing that I think needs to be addressed.

~/.nanorc is used to apply your user specific settings to nano, so if you are editing files that require the use of sudo nano for permissions then this is not going to work.

When using sudo your custom user configuration files will not be loaded when opening a program, as you are not running the program from your account so none of your configuration changes in ~/.nanorc will be applied.

If this is the situation you find yourself in (wanting to run sudo nano and use your own config settings) then you have three options :

  • using command line flags when running sudo nano
  • editing the /root/.nanorc file
  • editing the /etc/nanorc global config file

Keep in mind that /etc/nanorc is a global configuration file and as such it affects all users, which may or may not be a problem depending on whether you have a multi-user system.

Also, user config files will override the global one, so if you were to edit /etc/nanorc and ~/.nanorc with different settings, when you run nano it will load the settings from ~/.nanorc but if you run sudo nano then it will load the settings from /etc/nanorc.

Same goes for /root/.nanorc this will override /etc/nanorc when running sudo nano

Using flags is probably the best option unless you have a lot of options.