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newusers [options new_users]
The newusers command reads a file of user name and clear-text password
pairs and uses this information to update a group of existing users or
to create new users. Each line is in the same format as the standard
password file (see passwd(5)) with the exceptions explained below:
This is the name of the user.
It can be the name of a new user or the name of an existing user
(or an user created before by newusers). In case of an existing
user, the user?s information will be changed, otherwise a new user
will be created.
This field will be encrypted and used as the new value of the
This field is used to define the UID of the user.
If the field is empty, an new (unused) UID will be defined
automatically by newusers.
If this field contains a number, this number will be used as the
If this field contains the name of an existing user (or the name of
an user created before by newusers), the UID of the specified user
will be used.
If the UID of an existing user is changed, the files ownership of
the user?s file should be fixed manually.
This field is used to define the primary group ID for the user.
If this field contains the name of an existing group (or a group
created before by newusers), the GID of this group will be used as
the primary group ID for the user.
If this field is a number, this number will be used as the primary
group ID of the user. If no groups exist with this GID, a new group
will be created with this GID, and the name of the user.
If this field is empty, a new group will be created with the name
of the user and a GID will be automatically defined by newusers to
If this field does not specify an existing directory, the specified
directory is created, with ownership set to the user being created
or updated and its primary group.Note that newusers does not create
parent directories of the new user's home directory. The newusers
command will fail to create the home directory if the parent
directories do not exist, and will send a message to stderr
informing the user of the failure. The newusers command will not
halt or return a failure to the calling shell if it fails to create
the home directory, it will continue to process the batch of new
If the home directory of an existing user is changed, newusers does
not move or copy the content of the old directory to the new
location. This should be done manually.
This field defines the shell of the user. No checks are performed
on this field.
newusers first tries to create or change all the specified users, and
then write these changes to the user or group databases. If an error
occurs (except in the final writes to the databases), no changes are
committed to the databases.
This command is intended to be used in a large system environment where
many accounts are updated at a single time.
The options which apply to the newusers command are:
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.
Display help message and exit.
Create a system account.
System users will be created with no aging information in
/etc/shadow, and their numeric identifiers are choosen in the
SYS_UID_MIN-SYS_UID_MAX range, defined in login.defs, instead of
UID_MIN-UID_MAX (and their GID counterparts for the creation of
Use the specified number of rounds to encrypt the passwords.
The input file must be protected since it contains unencrypted
You should make sure the passwords and the encryption method respect
the system?s password policy.
The following configuration variables in /etc/login.defs change the
behavior of this tool:
This defines the system default encryption algorithm for encrypting
passwords (if no algorithm are specified on the command line).
It can take one of these values:
? DES (default)
Note: this parameter overrides the MD5_CRYPT_ENAB variable.
GID_MAX (number), GID_MIN (number)
Range of group IDs used for the creation of regular groups by
useradd, groupadd, or newusers.
Maximum members per group entry. When the maximum is reached, a
new group entry (line) is started in /etc/group (with the same
name, same password, and same GID).
The default value is 0, meaning that there are no limits in the
number of members in a group.
This feature (split group) permits to limit the length of lines
in the group file. This is useful to make sure that lines for
NIS groups are not larger than 1024 characters.
If you need to enforce such limit, you can use 25.
Note: split groups may not be supported by all tools (even in
the Shadow toolsuite). You should not use this variable unless
you really need it.
Indicate if passwords must be encrypted using the MD5-based
algorithm. If set to yes, new passwords will be encrypted using
password is older than this, a password change will be forced.
If not specified, -1 will be assumed (which disables the
The minimum number of days allowed between password changes.
Any password changes attempted sooner than this will be
rejected. If not specified, -1 will be assumed (which disables
The number of days warning given before a password expires. A
zero means warning is given only upon the day of expiration, a
negative value means no warning is given. If not specified, no
warning will be provided.
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
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
The values must be inside the 1000-999999999 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.
SYS_GID_MAX (number), SYS_GID_MIN (number)
Range of group IDs used for the creation of system groups by
useradd, groupadd, or newusers.
SYS_UID_MAX (number), SYS_UID_MIN (number)
Range of user IDs used for the creation of system users by
useradd or newusers.
UID_MAX (number), UID_MIN (number)
Range of user IDs used for the creation of regular users by
useradd or newusers.
The file mode creation mask is initialized to this value. If
not specified, the mask will be initialized to 022.
Secure user account information.
Group account information.
Secure group account information.
Shadow password suite configuration.
login.defs(5), passwd(1), useradd(8).
System Management Commands 07/24/2009 NEWUSERS(8)