User Info:
user:
Create a user, password: useradd: -d: Set the user's home directory -e: Set account expiration time -g: Specifies the user's primary group -p: specify a password -u: Specifies the user id
passwd: -k: Updates only the user's password expired passwd username
Query user information: cat / etc / passwd: query user UID and GID cat / etc / shadow: query user password (display encrypted passwords) chage -l username: View user id expiration time Username: uid and gid
Modify user information: su: switch user userdel: Delete User
usermod: -d: modify the user's home directory -e: user expiration time -G: Add the user to specify a group -u: modify user id
usermod -aG root (group name) 123 (user name) to modify the configuration file / etc / sudoers, remove the front of the ALLOW people #
user group:
Creating user groups, code: groupadd: -g 200 a: id created a group of 200 users
gpasswd: -a: Adding a user to a group -d: -A delete user to a group: set group administrators -M: set the team member
Modify user group information: groupmod: -g: Specifies the new group id -n: Specifies the new group name
Directory Structure:
etc: store configuration files
bin: to store users and administrators frequently used commands
sbin: storage administrator commonly used commands
home: home directory to store user files
root: root user's home directory storage
tmp: temporary run-time generated files
var: contains various data files, log, temporary files
usr: contains no modification of the program, the general store to install the software
boot: When storing documents required to start
system:
data: View System Time: data -s 'Time': Set Time
reboot: reboot
whoami: Displays the current user is located
who am i: displays the login user
who: displays all users