chgpasswd 8 System Management Commands chgpasswd update group passwords in batch mode chgpasswd options chgpasswd reads a list of group name and password pairs from standard input and uses this information to update a set of existing groups. Each line is of the format: group_name:password By default the supplied password must be in clear-text. Default encryption algorithm is DES. This command is intended to be used in a large system environment where many accounts are created at a single time. The options which apply to the chgpasswd command are: -e, --encrypted Supplied passwords are in encrypted form. -h, --help Display help message and exit. -m, --md5 Use MD5 encryption instead DES when the supplied passwords are not encrypted. Remember to set permissions or umask to prevent readability of unencrypted files by other users. gpasswd1 , groupadd8 .