Users
Linux has users of its os.
The multipass app gives a default user of ubuntu.
Detecting the current user with whoami
whoami is a command that returns the currently-logged-in user.
ubuntu@primary:~$ whoami
ubuntuAgain, ubuntu is the name of the user that multipass gives.
see all users with cat
# show ALL users on the machine
ubuntu@primary:~$ cat /etc/passwdUsers have permissions
Linux uses the "principle of least power" when it comes to users + permissions: users have the least permissions possible.
The super user and sudo
sudo is a super power. Switch User and do....
sudo with a user to switch to defaults to the root user.
root is a superuser that can be used with sudo su.
root can do everything.
It should be used with extreme caution.
Many things, like creating a new user, can only be done by the superuser.
# use the superuser called root
ubuntu@primary:~$ sudo su
root@primary:/home/ubuntu# whoami
root
# switch back to the ubuntu user
root@primary:/home/ubuntu# exit
exit
ubuntu@primary:~$ whoami
ubuntuAn Example
Creating A User
Only certain users can create other users:
# start as the ubuntu user (in a multipass prompt)
ubuntu@primary:~$ whoami
ubuntu
# try adding a user
ubuntu@primary:~$ useradd thisisme
useradd: Permission denied.
useradd: cannot lock /etc/passwd; try again later.
# switch to the root user
ubuntu@primary:~$ sudo su
root@primary:/home/ubuntu# whoami
root
# try adding the new user as the root user
root@primary:/home/ubuntu# useradd thisisme
# it worked!
# leave the root user
root@primary:/home/ubuntu# exitDeleting a User
Only certain users can create other users:
# start as the ubuntu user (in a multipass prompt)
ubuntu@primary:~$ whoami
ubuntu
# try deleting a user
ubuntu@primary:~$ userdel thisisme
userdel: Permission denied.
userdel: cannot lock /etc/passwd; try again later.
# switch to the root user
ubuntu@primary:~$ sudo su
root@primary:/home/ubuntu# whoami
root
# try deleting the new user as the root user
root@primary:/home/ubuntu# userdel thisisme
# it worked!
# leave the root user
root@primary:/home/ubuntu# exitOne-Line User switching
Running a command with the sudo prefix is a one-line way to be the root user.
ubuntu@primary:~$ whoami
ubuntu
ubuntu@primary:~$ sudo whoami
root
# sudo add a user + pwd
ubuntu@primary:~$ sudo useradd jake
ubuntu@primary:~$ sudo passwd jake
New password:
Retype new password:
passwd: password updated successfully
# change to 'jake' user
ubuntu@primary:~$ whoami
ubuntu
ubuntu@primary:~$ su jake
Password:
$ whoami
jake
# notice the prompt prefix changed! interesting
$ pwd
/home/ubuntu
# attempt to sudo su
$ sudo su
[sudo] password for jake:
jake is not in the sudoers file. This incident will be reported.