passwd

Overview

The passwd command changes user password. It modifies the password for user accounts and can also change account information.

Syntax

passwd [options] [username]

Common Options

Option Description
-d Delete password
-e Expire password
-i days Inactive days
-l Lock account
-n days Minimum days
-S Status report
-u Unlock account
-w days Warning days
-x days Maximum days
--stdin Read from stdin

Configuration Files

File Description
/etc/passwd User accounts
/etc/shadow Password data
/etc/pam.d/passwd PAM config
/etc/login.defs Login defaults
/etc/security/pwquality.conf Password quality

Key Use Cases

  1. Password changes
  2. Account security
  3. Password policy
  4. Account locking
  5. Security management

Examples with Explanations

Example 1: Change Password

passwd

Change own password

Example 2: User Password

passwd username

Change user’s password

Example 3: Lock Account

passwd -l username

Lock user account

Common Usage Patterns

  1. Self change:

    passwd

  2. User change:

    passwd user

  3. Account status:

    passwd -S user

Security Considerations

  1. Password strength
  2. Account access
  3. Expiry policy
  4. Lock control
  5. Password history

Additional Resources

Best Practices

  1. Strong passwords
  2. Regular changes
  3. Policy compliance
  4. Access control
  5. Documentation

Password Management

  1. Password changes
  2. Account security
  3. Policy enforcement
  4. Access control
  5. Security audit

Troubleshooting

  1. Password errors
  2. Lock issues
  3. Policy conflicts
  4. Access problems
  5. System errors

Common Issues

  1. Weak passwords
  2. Policy violations
  3. Lock problems
  4. Access denied
  5. System conflicts