User management

User management

• Managing users is a critical aspect of server management.
• In Ubuntu, the root user is disabled for safety.
• Management tasks requiring root access can be completed by using the sudo command by a user who is in the “admin” group.
• When you create a user during installation, that user is added automatically to the admin group.

Adding and deleting users

To add a user:

sudo adduser username

The image below shows the next part of the command.

To delete a user (will retain the home directory):

Install the package:

sudo apt-get install unattended-upgrades

To disable a user:

sudo passwd -l username

To enable a user:

sudo passwd -u username

Creating and deleting groups

To create a group:

sudo addgroup groupname

To delete a group:

sudo delgroup groupname

To add a user to a group:

sudo adduser username groupname

User profiles

By default, all new home directories can be accessed by everyone. You can enforce non-default access rights to new home directories by editing /etc/ adduser.conf:

Change “DIRMODE=0755”to “DIRMODE=0750”

The contents of this directory are modelled after the contents of /etc/skel.

Password policy

You can enforce strong user passwords by editing the password policy file /etc/pam.d/common-password.

For example, if you want to enforce a password with minimum 8 characters and maximum 14 characters, edit the password line to look like this:

password required pam_unix.so nullok obscure min=8 max=14 md5

Password expiration

To see the password expiry value for a user, use the “chage” command:

The chage tool is for changing password expiration date.

sudo chage -l username

To make changes:

sudo chage username

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