Managing Users & Groups

Managing Users

In Linux, user properties encompass various attributes and settings associated with a user account. These properties define the user's identity, permissions, and environment within the system. Here are the key user properties you can manage:

• Username

• Password

• UserID (UID)

• GroupID (GID)

• Comment

  • Additional information

  • Commonly used for full name

• Home directory (~)

• Default shell

User Data Files

Data is stored in /etc/passwd. Commonly there is x where the password is. Password hashes are stored in /etc/shadow.

User Management

Create User

useradd $options $username

Options: • -p, --pasword ◦ NOT RECOMMENDED • -u, --uid • -g, --gid • -s, --shell • -d, --home-dir • -c, --comment If option isn’t specified the defaults are used

Delete User

userdel $username

Edit User

usermod $options $username

Options: • -l, --login ◦ Change username • -p, --pasword ◦ NOT RECOMMENDED • -u, --uid • -g, --gid • -s, --shell • -d, --home-dir • -c, --comment If option isn’t specified then it is unchanged

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passwd $user

Changes user password interactively. Recommended

More

View user information

id $username

View all user details from /etc/passwd

getent passwd $username

View password expiration details

sudo chage -l $username

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Managing Groups

In Linux, group properties define the characteristics and settings associated with a group. Groups are used to manage sets of users and control their permissions and access rights. Here are the key properties of group:

• Group name

• Password

  • Generally not used

• GroupID (GID)

• Members

Group Data Files

Stored in /etc/group

Group Management

Create Group

groupadd $options $groupname

Options: • -g, --gid • -p, --password If option isn’t specified the defaults are used

Delete Group

groupdel $groupname

Edit Group

groupmod $options $groupname

Options: • -n, --new-name • -g, --gid • -p, --password If option isn’t specified then it is unchanged

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Users Group

To edit a user's group, witch is defaultyly built with the user, just add -G flag to useradd/usermod commands

You can use -aG flag to add group to a user.