user-permissionslisted

# User and Permission Management ## Overview Linux user management, group management, sudo configuration, ACL permissions and other skills. ## User Management ### View Users ```bash # Current user whoami id # User information id username finger username # All users cat /etc/passwd getent passwd # Logged in users who w last # Login history ``` ### User Operations ```bash # Create user useradd username useradd -m -s /bin/bash username # Create home directory, specify shell useradd -G group1,group2 username # Specify supplementary groups # Modify user usermod -aG groupname username # Add to group usermod -s /bin/zsh username # Change shell usermod -L username # Lock user usermod -U username # Unlock user # Delete user userdel username userdel -r username # Also delete home directory # Change password passwd username passwd -l username # Lock password passwd -u username # Unlock password chage -l username # View password policy ``` ## Group Management ### View Groups ```bash # User's groups groups username id -Gn username # All groups cat /etc/group getent group # Group members getent group groupname ``` ### Group Operations ```bash # Create group groupadd groupname groupadd -g 1001 groupname # Specify GID # Modify group groupmod -n newname oldname # Rename # Delete group groupdel groupname # Manage