Linux passwd Guide

Linux passwd Guide

Complete beginner-friendly guide to passwd on Linux, covering Arch Linux, CachyOS, and other distributions including changing passwords, password policies, and user password management.

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Table of Contents

1. Understanding passwd
2. Changing Passwords
3. Password Policies
4. User Password Management
5. Troubleshooting

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Understanding passwd

What is passwd?

passwd changes user passwords.

Uses:

• Change password: Update your password
• Set password: Set password for user
• Lock account: Disable account
• Password policies: Enforce policies

Why it matters:

• Security: Strong passwords protect system
• Account management: Control user access
• Compliance: Meet security requirements

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Changing Passwords

Change Your Password

Basic usage:

# Change your password
passwd

# Enter current password
# Enter new password
# Confirm new password

Change User Password

As root:

# Change user password
sudo passwd username

# Or as root
passwd username

# Enter new password

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Password Policies

Password Requirements

Common requirements:

• Minimum length: Usually 8+ characters
• Complexity: Mix of letters, numbers, symbols
• History: Can't reuse recent passwords
• Expiration: Password expires after time

Check Password Age

View password info:

# Check password age
chage -l username

# Or
passwd -S username

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User Password Management

Lock Account

Disable account:

# Lock account
sudo passwd -l username

# Unlock account
sudo passwd -u username

Expire Password

Force password change:

# Expire password
sudo passwd -e username

# User must change on next login

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Troubleshooting

Password Not Working

Reset password:

# As root
sudo passwd username

# Or boot from live USB
# Mount system
# chroot
# passwd username

Password Policy Errors

Check policies:

# Check PAM config
cat /etc/pam.d/passwd

# Check password requirements
passwd -S username

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Summary

This guide covered passwd usage, password management, and policies for Arch Linux, CachyOS, and other distributions.

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Next Steps

• User and Groups - User management
• PAM Guide - Authentication
• Security Configuration - Security
• passwd Documentation: man passwd

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This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.