User Management:
1. Add user:
common syntax; useradd user name
Common options:
-g: indicates the specified user group
-G: indicates the specified user's additional group
-u: uid, user id, uniquely identifies a user
2. Modify user:
Common syntax: usermod option username
-g: indicates the specified user group
-G: indicates the specified user's additional group
-u: uid, user id, uniquely identifies a user
-l new user name original user name: modify user name
3. Set password
passwd user name;
switch user: su user name
4. Delete user
Common syntax: userdel user name
Common options:
-r: delete the home directory while deleting
User group management:
Add user group:
common method: groupadd group name
User group modification:
common commands: groupmod -g 520 (new group id) -n new group name will be modified group name
Deletion of user group: groupdel group name (note that if there are users in the group, the group member must be deleted first)
