ОПИСАНИЕ
The userdel command modifies the system account files, deleting all entries that refer to the user name LOGIN. The named user must exist.
ПАРАМЕТРЫ
The options which apply to the userdel command are:
This option forces the removal of the user account, even if the user is still logged in. It also forces userdel to remove the user’s home directory and mail spool, even if another user uses the same home directory or if the mail spool is not owned by the specified user. If USERGROUPS_ENAB is defined to yes in /etc/login.defs and if a group exists with the same name as the deleted user, then this group will be removed, even if it is still the primary group of another user.
Note: This option is dangerous and may leave your system in an inconsistent state.
Файлы в домашнем каталоге пользователя будут удалены вместе с самим домашним каталогом и почтовым ящиком. Пользовательские файлы, расположенные в других файловых системах, нужно искать и удалять вручную.
The mail spool is defined by the MAIL_DIR variable in the login.defs file.
-R, —root CHROOT_DIR
Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. Only absolute paths are supported.
-P, —prefix PREFIX_DIR
Apply changes in the PREFIX_DIR directory and use the configuration files from the PREFIX_DIR directory. 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.
НАСТРОЙКА
The following configuration variables in /etc/login.defs change the behavior of this tool:
ФАЙЛЫ
Run-part files to execute during user deletion. The environment variable ACTION will be populated with userdel and SUBJECT with the username. userdel-pre.d will be executed prior to any user deletion. userdel-post.d will execute after user deletion. If a script exits non-zero then execution will terminate.
ВОЗВРАЩАЕМЫЕ ЗНАЧЕНИЯ
The userdel command exits with the following values:
ПРЕДОСТЕРЕЖЕНИЯ
userdel will not allow you to remove an account if there are running processes which belong to this account. In that case, you may have to kill those processes or lock the user’s password or account and remove the account later. The -f option can force the deletion of this account.
Вы должны вручную проверить все файловые системы, чтобы убедиться, что не осталось файлов, принадлежащих этому пользователю.
Нельзя удалить NIS атрибуты клиента NIS. Это необходимо сделать на NIS сервере.
If USERGROUPS_ENAB is defined to yes in /etc/login.defs, userdel will delete the group with the same name as the user. To avoid inconsistencies in the passwd and group databases, userdel will check that this group is not used as a primary group for another user, and will just warn without deleting the group otherwise. The -f option can force the deletion of this group.
СМОТРИТЕ ТАКЖЕ
Package name: core/shadow Version: 4.13-2 Upstream: https://github.com/shadow-maint/shadow Licenses: BSD Manuals: /listing/core/shadow/ Table of contents
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Users and groups
Users and groups are used on GNU/Linux for access control—that is, to control access to the system’s files, directories, and peripherals. Linux offers relatively simple/coarse access control mechanisms by default. For more advanced options, see ACL, Capabilities and PAM#Configuration How-Tos.
Overview
A user is anyone who uses a computer. In this case, we are describing the names which represent those users. It may be Mary or Bill, and they may use the names Dragonlady or Pirate in place of their real name. All that matters is that the computer has a name for each account it creates, and it is this name by which a person gains access to use the computer. Some system services also run using restricted or privileged user accounts.
Managing users is done for the purpose of security by limiting access in certain specific ways. The superuser (root) has complete access to the operating system and its configuration; it is intended for administrative use only. Unprivileged users can use several programs for controlled privilege elevation.
Any individual may have more than one account as long as they use a different name for each account they create. Further, there are some reserved names which may not be used such as «root».
Users may be grouped together into a «group», and users may be added to an existing group to utilize the privileged access it grants.
Note: The beginner should use these tools carefully and stay away from having anything to do with any other existing user account, other than their own.
Permissions and ownership
The UNIX operating system crystallizes a couple of unifying ideas and concepts that shaped its design, user interface, culture and evolution. One of the most important of these is probably the mantra: «everything is a file,» widely regarded as one of the defining points of UNIX. This key design principle consists of providing a unified paradigm for accessing a wide range of input/output resources: documents, directories, hard-drives, CD-ROMs, modems, keyboards, printers, monitors, terminals and even some inter-process and network communications. The trick is to provide a common abstraction for all of these resources, each of which the UNIX fathers called a «file.» Since every «file» is exposed through the same API, you can use the same set of basic commands to read/write to a disk, keyboard, document or network device.
A fundamental and very powerful, consistent abstraction provided in UNIX and compatible operating systems is the file abstraction. Many OS services and device interfaces are implemented to provide a file or file system metaphor to applications. This enables new uses for, and greatly increases the power of, existing applications — simple tools designed with specific uses in mind can, with UNIX file abstractions, be used in novel ways. A simple tool, such as cat, designed to read one or more files and output the contents to standard output, can be used to read from I/O devices through special device files, typically found under the /dev directory. On many systems, audio recording and playback can be done simply with the commands, » cat /dev/audio > myfile » and » cat myfile > /dev/audio ,» respectively.
Every file on a GNU/Linux system is owned by a user and a group. In addition, there are three types of access permissions: read, write, and execute. Different access permissions can be applied to a file’s owning user, owning group, and others (those without ownership). One can determine a file’s owners and permissions by viewing the long listing format of the ls command:
total 13740 drwxr-xr-x 2 root root 4096 Jan 12 00:33 grub -rw-r--r-- 1 root root 8570335 Jan 12 00:33 initramfs-linux-fallback.img -rw-r--r-- 1 root root 1821573 Jan 12 00:31 initramfs-linux.img -rw-r--r-- 1 root root 1457315 Jan 8 08:19 System.map26 -rw-r--r-- 1 root root 2209920 Jan 8 08:19 vmlinuz-linux
The first column displays the file’s permissions (for example, the file initramfs-linux.img has permissions -rw-r—r— ). The third and fourth columns display the file’s owning user and group, respectively. In this example, all files are owned by the root user and the root group.
total 16 drwxrwx--- 1 root vboxsf 16384 Jan 29 11:02 sf_Shared
In this example, the sf_Shared directory is owned by the root user and the vboxsf group. It is also possible to determine a file’s owners and permissions using the stat command: