Skip to content

user-management.md

Latest commit

 

History

History
101 lines (84 loc) · 2.36 KB

user-management.md

File metadata and controls

101 lines (84 loc) · 2.36 KB
Raw

Linux User Management

What Are Users in Linux?

Users in Linux are accounts that identify who is using the system and control access to files, processes, and resources. Each user is associated with unique identifiers:

  • UID (User ID): A number assigned to identify the user.
  • GID (Group ID): The primary group the user belongs to.
  • Home Directory: A private space for the user.
  • Shell: The command-line interface for the user.

User Structure

graph TD
  A[Linux System]
  A --> B[Root User]
  A --> C[System Users]
  A --> D[Regular Users]

  C --> E[postgres]
  D --> F[boris]
  D --> G[testuser]
Loading

Basic User Management Commands

Check Existing Users

List all users on the system:

cat /etc/passwd
  • Each line represents a user account in the format: username:x:UID:GID:comment:home_directory:shell

Create a New User

Create a user with a home directory and prompt for a password:

sudo adduser testuser
  • testuser: The name of the new user.
  • Prompts for a password and creates /home/testuser.

Set or Reset a Password

Assign a new password to a user:

sudo passwd testuser
  • Prompts for a new password.
  • Updates the password for testuser.

Switch to Another User

Change to a different user account:

su - testuser
  • -: Loads the new user’s environment (e.g., .bashrc).
  • Prompts for the user’s password.

Delete a User

Remove a user account:

sudo deluser testuser
  • --remove-home: Also deletes the user’s home directory.

View User Details

Check details for a specific user:

grep testuser /etc/passwd
  • Displays the account’s configuration.

Unlock a Locked User

Ensure a user is not locked:

sudo passwd -u testuser
  • Unlocks the account if it was locked.

File Permissions

View file ownership and permissions:

ls -l
  • Example output: -rw-r--r-- 1 boris boris 1024 Dec 20 file.txt
    • Owner: boris
    • Group: boris

Change file ownership:

sudo chown testuser file.txt
  • Assigns ownership to testuser.

Best Practices for User Management

  1. Use separate users for different roles (e.g., database administration).
  2. Avoid running processes as root unless necessary.
  3. Regularly audit user accounts to ensure proper permissions.
  4. Test configurations or scripts with isolated test users.