User Management

Manage users, groups, and permissions.

User Operations

Create user

useradd -m -s /bin/bash username passwd username

Delete user

userdel -r username

Modify user

usermod -aG sudo username usermod -s /bin/zsh username

Group Management

Create group

groupadd developers

Add user to group

usermod -aG developers username gpasswd -a username developers

Remove from group

gpasswd -d username developers

Sudo Configuration

/etc/sudoers.d/developers

%developers ALL=(ALL) NOPASSWD: /usr/bin/docker username ALL=(ALL) NOPASSWD: ALL

File Permissions

chmod 755 file # rwxr-xr-x chmod u+x file # Add execute for user chown user:group file # Change ownership chown -R user:group dir/

ACLs

setfacl -m u:user:rx file getfacl file

Best Practices

• Use groups for access control

• Minimal sudo privileges

• Regular access reviews

• Strong password policies