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MAN page from OpenSuSE shadow-4.6-lp151.2.3.2.x86_64.rpm

USERMOD

Section: System Management Commands (8)
Updated: 04/29/2018
Index 

NAME

usermod - modify a user account 

SYNOPSIS

usermod [options] LOGIN
 

DESCRIPTION

Theusermodcommand modifies the system account files to reflect the changes that are specified on the command line. 

OPTIONS

The options which apply to theusermodcommand are:

-a, --append

Add the user to the supplementary group(s). Use only with the-Goption.

-c, --comment COMMENT

The new value of the user's password file comment field. It is normally modified using thechfn(1)utility.

-d, --home HOME_DIR

The user's new login directory.

If the-moption is given, the contents of the current home directory will be moved to the new home directory, which is created if it does not already exist.

-e, --expiredate EXPIRE_DATE

The date on which the user account will be disabled. The date is specified in the formatYYYY-MM-DD.

An emptyEXPIRE_DATEargument will disable the expiration of the account.

This option requires a/etc/shadowfile. A/etc/shadowentry will be created if there were none.

-f, --inactive INACTIVE

The number of days after a password expires until the account is permanently disabled.

A value of 0 disables the account as soon as the password has expired, and a value of -1 disables the feature.

This option requires a/etc/shadowfile. A/etc/shadowentry will be created if there were none.

-g, --gid GROUP

The group name or number of the user's new initial login group. The group must exist.

Any file from the user's home directory owned by the previous primary group of the user will be owned by this new group.

The group ownership of files outside of the user's home directory must be fixed manually.

-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]

A list of supplementary groups which the user is also a member of. Each group is separated from the next by a comma, with no intervening whitespace. The groups are subject to the same restrictions as the group given with the-goption.

If the user is currently a member of a group which is not listed, the user will be removed from the group. This behaviour can be changed via the-aoption, which appends the user to the current supplementary group list.

-l, --login NEW_LOGIN

The name of the user will be changed fromLOGINtoNEW_LOGIN. Nothing else is changed. In particular, the user's home directory or mail spool should probably be renamed manually to reflect the new login name.

-L, --lock

Lock a user's password. This puts a '!' in front of the encrypted password, effectively disabling the password. You can't use this option with-por-U.

Note: if you wish to lock the account (not only access with a password), you should also set theEXPIRE_DATEto1.

-m, --move-home

Move the content of the user's home directory to the new location.

This option is only valid in combination with the-d(or--home) option.

usermodwill try to adapt the ownership of the files and to copy the modes, ACL and extended attributes, but manual changes might be needed afterwards.

-o, --non-unique

When used with the-uoption, this option allows to change the user ID to a non-unique value.

-p, --password PASSWORD

The encrypted password, as returned bycrypt(3).

Note:This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.

You should make sure the password respects the system's password policy.

-R, --root CHROOT_DIR

Apply changes in theCHROOT_DIRdirectory and use the configuration files from theCHROOT_DIRdirectory.

-P, --prefix PREFIX_DIR

Apply changes in thePREFIX_DIRdirectory and use the configuration files from thePREFIX_DIRdirectory. This option does not chroot and is intended for preparing a cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified. PAM authentication is using the host files. No SELINUX support.

-s, --shell SHELL

The name of the user's new login shell. Setting this field to blank causes the system to select the default login shell.

-u, --uid UID

The new numerical value of the user's ID.

This value must be unique, unless the-ooption is used. The value must be non-negative.

The user's mailbox, and any files which the user owns and which are located in the user's home directory will have the file user ID changed automatically.

The ownership of files outside of the user's home directory must be fixed manually.

No checks will be performed with regard to theUID_MIN,UID_MAX,SYS_UID_MIN, orSYS_UID_MAXfrom/etc/login.defs.

-U, --unlock

Unlock a user's password. This removes the '!' in front of the encrypted password. You can't use this option with-por-L.

Note: if you wish to unlock the account (not only access with a password), you should also set theEXPIRE_DATE(for example to99999, or to theEXPIREvalue from/etc/default/useradd).

-v, --add-subuids FIRST-LAST

Add a range of subordinate uids to the user's account.

This option may be specified multiple times to add multiple ranges to a users account.

No checks will be performed with regard toSUB_UID_MIN,SUB_UID_MAX, orSUB_UID_COUNTfrom /etc/login.defs.

-V, --del-subuids FIRST-LAST

Remove a range of subordinate uids from the user's account.

This option may be specified multiple times to remove multiple ranges to a users account. When both--del-subuidsand--add-subuidsare specified, the removal of all subordinate uid ranges happens before any subordinate uid range is added.

No checks will be performed with regard toSUB_UID_MIN,SUB_UID_MAX, orSUB_UID_COUNTfrom /etc/login.defs.

-w, --add-subgids FIRST-LAST

Add a range of subordinate gids to the user's account.

This option may be specified multiple times to add multiple ranges to a users account.

No checks will be performed with regard toSUB_GID_MIN,SUB_GID_MAX, orSUB_GID_COUNTfrom /etc/login.defs.

-W, --del-subgids FIRST-LAST

Remove a range of subordinate gids from the user's account.

This option may be specified multiple times to remove multiple ranges to a users account. When both--del-subgidsand--add-subgidsare specified, the removal of all subordinate gid ranges happens before any subordinate gid range is added.

No checks will be performed with regard toSUB_GID_MIN,SUB_GID_MAX, orSUB_GID_COUNTfrom /etc/login.defs.

-Z, --selinux-user SEUSER

The new SELinux user for the user's login.

A blankSEUSERwill remove the SELinux user mapping for userLOGIN(if any).

 

CAVEATS

You must make certain that the named user is not executing any processes when this command is being executed if the user's numerical user ID, the user's name, or the user's home directory is being changed.usermodchecks this on Linux. On other platforms it only uses utmp to check if the user is logged in.

You must change the owner of anycrontabfiles oratjobs manually.

You must make any changes involving NIS on the NIS server. 

CONFIGURATION

The following configuration variables in/etc/login.defschange the behavior of this tool:

MAIL_DIR (string)

The mail spool directory. This is needed to manipulate the mailbox when its corresponding user account is modified or deleted. If not specified, a compile-time default is used.

MAIL_FILE (string)

Defines the location of the users mail spool files relatively to their home directory.

TheMAIL_DIRandMAIL_FILEvariables are used byuseradd,usermod, anduserdelto create, move, or delete the user's mail spool.

IfMAIL_CHECK_ENABis set toyes, they are also used to define theMAILenvironment variable.

MAX_MEMBERS_PER_GROUP (number)

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.

SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)

If/etc/subuidexists, the commandsuseraddandnewusers(unless the user already have subordinate group IDs) allocateSUB_GID_COUNTunused group IDs from the rangeSUB_GID_MINtoSUB_GID_MAXfor each new user.

The default values forSUB_GID_MIN,SUB_GID_MAX,SUB_GID_COUNTare respectively 100000, 600100000 and 10000.

SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)

If/etc/subuidexists, the commandsuseraddandnewusers(unless the user already have subordinate user IDs) allocateSUB_UID_COUNTunused user IDs from the rangeSUB_UID_MINtoSUB_UID_MAXfor each new user.

The default values forSUB_UID_MIN,SUB_UID_MAX,SUB_UID_COUNTare respectively 100000, 600100000 and 10000.

 

FILES

/etc/group

Group account information.

/etc/gshadow

Secure group account information.

/etc/login.defs

Shadow password suite configuration.

/etc/passwd

User account information.

/etc/shadow

Secure user account information.

/etc/subgid

Per user subordinate group IDs.

/etc/subuid

Per user subordinate user IDs.
 

SEE ALSO

chfn(1),chsh(1),passwd(1),crypt(3),gpasswd(8),groupadd(8),groupdel(8),groupmod(8),login.defs(5),subgid(5), subuid(5),useradd(8),userdel(8).


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
CAVEATS
CONFIGURATION
FILES
SEE ALSO

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