обновлять пароли в пакетном режиме (update passwords in batch mode)
Имя (Name)
chpasswd - update passwords in batch mode
Синопсис (Synopsis)
chpasswd [options]
Описание (Description)
The chpasswd command reads a list of user name and password pairs
from standard input and uses this information to update a group
of existing users. Each line is of the format:
user_name:password
By default the passwords must be supplied in clear-text, and are
encrypted by chpasswd. Also the password age will be updated, if
present.
By default, passwords are encrypted by PAM, but (even if not
recommended) you can select a different encryption method with
the -e, -m, or -c options.
Except when PAM is used to encrypt the passwords, chpasswd first
updates all the passwords in memory, and then commits all the
changes to disk if no errors occurred for any user.
When PAM is used to encrypt the passwords (and update the
passwords in the system database) then if a password cannot be
updated chpasswd continues updating the passwords of the next
users, and will return an error code on exit.
This command is intended to be used in a large system environment
where many accounts are created at a single time.
Параметры (Options)
The options which apply to the chpasswd command are:
-c, --crypt-method METHOD
Use the specified method to encrypt the passwords.
The available methods are DES, MD5, NONE, and SHA256 or
SHA512 if your libc support these methods.
By default, PAM is used to encrypt the passwords.
-e, --encrypted
Supplied passwords are in encrypted form.
-h, --help
Display help message and exit.
-m, --md5
Use MD5 encryption instead of DES when the supplied passwords
are not encrypted.
-R, --root CHROOT_DIR
Apply changes in the CHROOT_DIR directory and use the
configuration files from the CHROOT_DIR directory.
-s, --sha-rounds ROUNDS
Use the specified number of rounds to encrypt the passwords.
The value 0 means that the system will choose the default
number of rounds for the crypt method (5000).
A minimal value of 1000 and a maximal value of 999,999,999
will be enforced.
You can only use this option with the SHA256 or SHA512 crypt
method.
By default, the number of rounds is defined by the
SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in
/etc/login.defs.
Предостережение (Caveat)
Remember to set permissions or umask to prevent readability of
unencrypted files by other users.
Конфигурация (Configuration)
The following configuration variables in /etc/login.defs change
the behavior of this tool:
SHA_CRYPT_MIN_ROUNDS (number), SHA_CRYPT_MAX_ROUNDS (number)
When ENCRYPT_METHOD is set to SHA256 or SHA512, this defines
the number of SHA rounds used by the encryption algorithm by
default (when the number of rounds is not specified on the
command line).
With a lot of rounds, it is more difficult to brute forcing
the password. But note also that more CPU resources will be
needed to authenticate users.
If not specified, the libc will choose the default number of
rounds (5000), which is orders of magnitude too low for
modern hardware.
The values must be inside the 1000-999,999,999 range.
If only one of the SHA_CRYPT_MIN_ROUNDS or
SHA_CRYPT_MAX_ROUNDS values is set, then this value will be
used.
If SHA_CRYPT_MIN_ROUNDS > SHA_CRYPT_MAX_ROUNDS, the highest
value will be used.
Note: This only affect the generation of group passwords. The
generation of user passwords is done by PAM and subject to
the PAM configuration. It is recommended to set this variable
consistently with the PAM configuration.
Файлы (Files)
/etc/passwd
User account information.
/etc/shadow
Secure user account information.
/etc/login.defs
Shadow password suite configuration.
/etc/pam.d/chpasswd
PAM configuration for chpasswd.
Смотри также (See also)
passwd(1), newusers(8), login.defs(5), useradd(8).
