Ubuntu – What do the `–disabled-login` and `–gecos` options of `adduser` command stand for

addusercommand line

Running Ubuntu 12.04, I setup a private git server and created a group called git some time ago. Now I am following a guide to install gitlab and when it came to adding a user to the git group and create it, I saw that I already had it.

The command is this:

sudo adduser --disabled-login --gecos 'GitLab' git

taken from Gitlab installation Tutorial.

I would like to understand that command correctly. For me I thought I add a user to a group like this:

adduser user group

So what do --disabled-login and --gecos stand for?

Best Answer

It's all written in the manual page!

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You don't need to install something, to search on google or to have an internet connection. Just open your terminal and first of all you must to run the following command:

man adduser

to open the manual page for adduser command.

Then, in that manual page type: /--disabled-login followed by Enter then press repetitively n to find all occurrences containing --disabled-login. Do the same for --gecos.

With a little bit of luck you will find out that:

--disabled-login
          Do not run passwd to set the password.  The user won't be able 
          to use  her  account until the password is set.

and:

--gecos GECOS
          Set  the  gecos field for the new entry generated.  adduser will 
          not ask for finger information if this option is given.

For those wondering what gecos actually is, wikipedia defines it as follows:

The gecos field, or GECOS field is an entry in the /etc/passwd file on Unix, and similar operating systems. It is typically used to record general information about the account or its user(s) such as their real name and phone number.

Related Solutions

How to Login as Non-Root User in Terminal

To which user you want to change to?

The problem is that you are trying to "su" into a user that does not have a shell assigned to it. Most of the users such as mysql, pulse, etc, created by the system or by some packages when you install software does not have a shell assigned.

You can check if a user has a shell assigned by looking into the /etc/passwd file, just look at the end of the line of each user, if it says /bin/false it means that it does not have a shell assigned, if it has something like /bin/bash or any other shell, then you should be able to "su" into that user.

When i say "shell assigned" it basically means that it has "shell access"

still if the user does not have shell access, you can always execute commands as that user with

 sudo -u user command

What Does ~$ Stand For in Command Line?

The ~ and $ are elements of the command line prompt. This indicates that your computer (or more exactly, I guess, the shell you are running) is waiting for user input. It is prompting you to input a command.

The $ is merely a separator or divider. It separates the command prompt from the command which follows it. When people write such things as $ sudo apt-get update (your example), they are simply telling you that the command, in this case sudo apt-get update, needs to be entered at a command prompt. Strictly speaking, perhaps, the $ is redundant in this context.

Other separators may be used in other situations. For example, # is used for a root shell.

The ~ (called 'tilde') is shorthand for your home directory. When it appears in a command prompt, e.g., user@hostame:~$, it indicates that the current working directory is your home directory. Thus if you run the list command, ls, without specifying any particular directory, it will list the contents of your home directory.

(By the way, $HOME, is not a command, as you suggest, but rather an environment variable. It determines the location of your home directory. You can see its value by running $ echo $HOME.)

Best Answer

It's all written in the manual page!

Related Solutions

How to Login as Non-Root User in Terminal

What Does ~$ Stand For in Command Line?

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