Linux User and Group management

Linux User and Group management

Security context:
The process runs as its initiator:
The process's access to the file depends on the permissions of the user initiating the process

系统用户: 为了能够让那些后台进程或服务类进程以非管理员身份运行，通常需要为此创建多个普通用户，这类用户不用登陆系统:

Groupadd command: Adding a group

     Groupadd [Options] group-g gid: Specify GID: Default is gid+1 of previous group:-r: Create System Group: Groupmod Command: Modify group information groupmod [options] Group-g GID: Modify GID:-N new_name: Modify group Name: Groupdel command: Groupdel [options] groupusreadd command: Create user Useradd [opt Ions] login-u,--uid uid: Specify UID:-G,--gid Group: Specifies the base group ID, which must exist beforehand:-G,--groups group1[,group2,... [, GROUPN]]: Indicates the additional group to which the user belongs, separated by commas between multiple organizations:-C,--comment Comment: Indicates annotation information:-D,--home-dir Home_dir: The home directory of the user with the specified path: Pass Copy/etc/skel This directory and rename the implementation: The specified home directory path does not replicate the configuration environment profile for users if it exists beforehand:-S,--shell Shell: Specifies the user default shell, all available shell lists are stored in the/etc/shell file Medium:-R,--system: Create System User:-M,--create-home: Do not create a home directory for users note: Creating a user is a lot of the default configuration files are/etc/login.defs useradd- D: Display default configuration for creating User: useradd-d option: Modify default option Value "" The result of the modification is saved in the/etc/default/useradd file usermod command: Modify user options Usermod [option S] login-u,--uid uid: Modify Uid-g,--gid Group: Modify the basic group to which the user belongs:-G,--groups group1[,group2,... [, GROUPN]]: Modifies the additional group to which the user belongs: The original additional group is overwritten:       -A,--append: Used with-large g to append a new additional group to the user:-C,--comment Comment: Modify annotation information:-D,--home-dir Home_dir: Modify the user's home directory  : User's original files will not be transferred to the new location:-M,--move-home: can only be consumed with the-D option to move the original home directory to the new home directory:-L,--login new_login: Modify user name:-S, --shell Shell: Modify user Default shell-l,--lock: Lock user password: That is, before the user's original password string to add a "! ":-U,--unlock: Unlock user's password: Userdel command: Delete user Userdel [options] login-r: Delete home directory when user is deleted:

Linux user and group management