3. User Types and Login
👥 User Categories
| 🔴 Administrator (Privileged User) |
💚 Regular User (Unprivileged User) |
|
**Username:** `root`
✅ Full system access
✅ Can modify any file or setting
✅ Can install software system-wide
🔴 Prompt ends with `#`
|
**Username:** varies (`alice`, `bob`, etc.)
⚠️ Limited system access
✅ Can modify files in home directory
❌ Cannot change system settings
💚 Prompt ends with `$`
|
🔄 Switching Users
📋 Quick Reference
| Command |
Description |
Password Required |
su - <username> |
Switch to another user |
User’s password |
su - |
Switch to root |
Root password |
sudo su |
Switch to root |
Your password |
sudo <command> |
Run single command as root |
Your password |
sudo -i |
Interactive root shell (root environment) |
Your password |
sudo -s |
Interactive root shell (user environment) |
Your password |
💻 Command Examples
# Switch to another regular user (- can be omitted)
su - alice
# Switch to root account (prompts for Root password)
su -
# Switch to root account (prompts for User password)
sudo su
# Run single command as another user (root or administrator in that case)
sudo apt update
# Run command as specific user
sudo -u postgres psql
# Get interactive root shell
# Switches to Root environment (home)
sudo -i
# or (Remains in user environment)
sudo -s
🔍 Who’s Logged In?
# Show all logged in users
who
┌──────────────────────────────────┐
│ alice tty1 2024-02-08 10:30 │
│ bob pts/0 2024-02-08 11:15 │
└──────────────────────────────────┘
# Show information about current session
who am i
# Show current username
whoami
alice
# Show detailed user activity
w
┌───────────────────────────────────────────────────┐
│ USER TTY LOGIN@ IDLE WHAT │
│ alice pts/0 10:30 0.00s w │
│ bob pts/1 11:15 5:30 vim document.txt │
└───────────────────────────────────────────────────┘
Navigation
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Course Home: ⌂ Introduction to Linux