User management in Linux

In Linux can have multiple users. To manage multiple users effectively you need to know
how to handle a user account – add, delete, edit and suspend user account.

Add user account

To add an user from terminal you have to run command useradd
Syntax

useradd username

Example

useradd adatt

After adding user you will need to create password for user.
Syntax

passwd username

Example

passwd test

passwords for user are stored in /etc/passwd file.

Add user account with full user name

You can also provide full user name  by using –c switch with useradd command.

Syntax

useradd –c “Full username” username

Example

useradd –c “ A Datt” adatt

Add user account with specified UID

Whenever user is created in Linux system an UID is assigned to it. This UID is generated by system. Also home directory is created for user – /home/username.

You can create a user with any custom UID specified. For creating UID for user you will have to use –c switch.

Syntax

useradd –u 1572 username

Example

useradd –u 1572 adatt

Add user account with account expiry date

An user account can be created with an expiry date. The default expiry date of any user is set to 0 i.e. user account will never expire.
For creating a user account with account expiry date, use switch –e. The expiry date is to given in YYYY-MM-DD format.
Syntax

useradd –e YYYY-MM-DD username

Example

useradd –e 2017-09-25 adatt

This user will expire on 25 September 2017

Add user account with password expiry date

For security reasons a admin may want user to change password after every few day. Linux has an inbuilt option where an user account can be created with an expiry date using chage command. For creating a user account with password expiry date, use switch –f. Post this date user account will be made inactive by system
Syntax

useradd –f days username

Example

useradd –f 45 adatt

Creating a user with a home directory other than default

To set home directory of an user to a non-default home directory, we will have to use switch –c.
Syntax

useradd –d /home/xxxxx username

Example

useradd –d /home/developer adatt