chpasswd

batch update user passwords

TLDR

Change the password for a specific user

$ printf "[username]:[new_password]" | sudo chpasswd

Change passwords for multiple users

$ printf "[username_1]:[password_1]\n[username_2]:[password_2]" | sudo chpasswd

Change password using an encrypted form

$ printf "[username]:[encrypted_password]" | sudo chpasswd -e

Change password with specific encryption method

$ printf "[username]:[new_password]" | sudo chpasswd -c [SHA512]

chpasswd reads username:password pairs from standard input and updates user passwords in batch. This is useful for system administration tasks requiring password changes for multiple users at once, such as during initial account provisioning or automated password rotation.Input format is one user per line as username:password with no spaces around the colon. Passwords are encrypted using the system default method (typically SHA-512) unless a different method is specified. Pre-encrypted passwords can also be supplied with the -e flag.

PARAMETERS

-e, --encrypted

Passwords are supplied in encrypted form

-c, --crypt-method method

Specify encryption method (NONE, DES, MD5, SHA256, SHA512)

-m, --md5

Use MD5 encryption

-s, --sha-rounds rounds

Number of rounds for SHA encryption

CONFIGURATION

/etc/login.defs

Controls default encryption method (ENCRYPTMETHOD), SHA rounds (SHACRYPTMINROUNDS, SHACRYPTMAX_ROUNDS), and other password policy settings used by chpasswd.

INSTALL

sudo apt install passwd

sudo pacman -S shadow

sudo apk add shadow

sudo zypper install shadow

nix profile install nixpkgs#shadow

CAVEATS

Requires root privileges. Passwords passed via command line may be visible in process listings. Consider using encrypted passwords or secure input methods in scripts. DES encryption is considered weak.

HISTORY

chpasswd is part of the shadow-utils package for batch password management.