Root vs. Non-privileged Users. Getting Root Access (sudo, su, passwd):

👤 Root vs. Non-privileged Users

Linux has two primary types of users:

Root (Superuser) - The most powerful user with absolute system privileges.
Non-privileged (Normal) Users - Regular users with limited access.

⚡ Root Privileges

Root can:

Run any command
Access any file on the system
Install/update software
Manage user accounts
Administer services

Warning: Avoid using the root account for regular tasks (e.g., browsing the web, writing documents) because a small mistake could damage the entire system.

🔐 Non-privileged User Restrictions

Non-privileged users:

Cannot perform administrative tasks (e.g., installing software, creating users)
Limited to their own home directory

For administrative tasks, sudo or su is used to temporarily gain root privileges.

🛠️ Ways to Gain Root Access

1. Using `sudo su`

sudo (Super User Do) allows a user to run commands with root privileges.
su (Substitute User) allows switching to another user (typically root).

Steps:

sudo su

Enter your user password (not root's).
A new shell with root privileges starts.
Run administrative commands.

2. Using `sudo` Directly

Prefix a command with sudo to execute it as root:

sudo command

Enter your password.
The command runs with root privileges.

Example:

Running a command without sudo might give a "permission denied" error:

groupadd mygroup

Now using sudo:

sudo groupadd mygroup

🔒 Password Caching in `sudo`

After running sudo, credentials are cached for 5 minutes.
You don’t need to re-enter your password during this window.

To reset the cache:

sudo -k

📝 Changing the Root Password

By default, root account access is locked on distributions like Ubuntu.
To unlock it, set the root password:

sudo passwd root

Now you can use su to temporarily become root:

su

Enter the newly set root password.

🏠 Understanding the Root Directory

Root Directory /: The top-level directory of the Linux file system.
Root User's Home Directory /root: This is the home directory for the root user.
Non-root User's Home Directory /home/username: Home directories for normal users are created here.