Q5. Why /etc/passwd and /etc/shadow cannot be merged?

Answer:

• /etc/passwd → world-readable (username, UID, GID, shell)

• /etc/shadow → root-only (encrypted passwords)

Reason: Security.

If both files were merged, password hashes would be exposed, leading to credential theft and brute-force attacks.

Production :

In production systems, applications and services need to read user information from /etc/passwd.
Keeping password hashes in /etc/shadow ensures authentication security without breaking system functionality.

Interview One-Liner:

“/etc/passwd and /etc/shadow are separate to protect password hashes—merging them would expose credentials and compromise security.”