Tool for batch updating user passwords
The chpasswd command is a tool for batch updating user passwords. It reads a list of user/password pairs from standard input and updates the system's password files (typically /etc/shadow).
chpasswd [options]
-e: The input passwords are already encrypted;
-h: Display help information and exit;
-m: Use MD5 encryption instead of DES when unsupported passwords are not encrypted.
First, create a file containing user-password pairs in the format username:password, e.g., abc:abc123. The file must follow this format strictly, with no empty lines. Save it as user.txt, then execute the chpasswd command:
chpasswd < user.txt
This is how the chpasswd command is used to batch modify passwords, which is a shortcut in Linux system administration.