passwd command

`passwd` - change user password

The passwd command in Linux is a utility used to change user passwords or manage password-related settings for user accounts. It’s essential for securing accounts and enforcing password policies.

Note: Regular users can change their own passwords, but changing another user’s password or locking accounts requires root privileges (sudo).

Usage: passwd [options] [LOGIN]

LOGIN: The user whose password to change (optional; defaults to current user).
options: Flags to modify behavior (e.g., lock, expire).

Common Options Summary

Option	Description
`-l`	Lock the account
`-u`	Unlock the account
`-e`	Expire the password (force change)
`-S`	Show password status
`-d`	Delete the password (no login)
`-n`	Set minimum days before change
`-x`	Set maximum days before expiration

Examples

Changing Your Own Password

Run passwd without arguments to update your own password.
```
passwd
```
- Prompts:
```
Enter current password:
Enter new password:
Retype new password:
```
- Updates your password if the current one is correct and the new one meets policy (e.g., length).
Changing Another User’s Password

As root, specify a username to change their password.
```
sudo passwd alice
```
- Prompts for a new password for alice.
- Useful for admins setting initial passwords.
Locking an Account

Use -l to lock a user’s account, preventing login.
```
sudo passwd -l bob
```
- Adds ! to the password field in /etc/shadow, disabling login.
- Check: grep bob /etc/shadow (shows ! before hash).
Unlocking an Account

Use -u to unlock a locked account.
```
sudo passwd -u bob
```
- Removes the !, restoring login ability.
Forcing Password Change

Use -e to expire a password, forcing the user to change it at next login.
```
sudo passwd -e alice
```
- Sets the password’s last change date to 0 in /etc/shadow.
- Next login: alice must set a new password.
Checking Password Status

Use -S to see a user’s password status.
```
sudo passwd -S alice
```
- Output: alice P 04/01/2025 0 99999 7 -1
- Explanation:
  - P: Password set (or L for locked, NP for no password).
  - 04/01/2025: Last change.
  - 0 99999 7 -1: Policy settings (min days, max days, warning, inactivity).

To get help related to the `passwd` command use `--help` option

$ passwd --help
Usage: passwd [options] [LOGIN]

Options:
  -a, --all                     report password status on all accounts
  -d, --delete                  delete the password for the named account
  -e, --expire                  force expire the password for the named account
  -h, --help                    display this help message and exit
  -k, --keep-tokens             change password only if expired
  -i, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -l, --lock                    lock the password of the named account
  -n, --mindays MIN_DAYS        set minimum number of days before password
                                change to MIN_DAYS
  -q, --quiet                   quiet mode
  -r, --repository REPOSITORY   change password in REPOSITORY repository
  -R, --root CHROOT_DIR         directory to chroot into
  -S, --status                  report password status on the named account
  -u, --unlock                  unlock the password of the named account
  -w, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS
  -x, --maxdays MAX_DAYS        set maximum number of days before password
                                change to MAX_DAYS

For more details, check the manual with man passwd

passwd - change user password​

Examples​

To get help related to the passwd command use --help option​

`passwd` - change user password

Examples

To get help related to the `passwd` command use `--help` option