Linux account management and ACL permissions settings

first, Linux users and user groups
1. The Linux user account is located in the/etc/passwd password located in/etc/shadow
User group account is located in the/etc/group password located in/etc/gshadow
2. Groups: View valid user groups and support user groups enter commands directly groups
The first output user group is a valid user group
3. NEWGRP: Switch NEWGRP user Group for effective user group

second, account management (System administrator)
1, Useradd: Add account User [u UID] [-G initial user Group] [-G secondary user group] [-mm] [-C description document] [-D main file absolute path] [-s shell] user account name
2, passwd: Set the password passwd [-l] [-u] [–stdin] [-S] [-N days] [-X days] [-W days] [-I date] Account
3, Chage: Display or modify the account password Chage [-LDEIMMW] account name
-L: Lists the detailed password parameters for this account
4, Usermod: Account modification Usermod [-cdegglsulu] Username
5. Userdel: Delete User Userdel [-r] Username
-R: Along with the user's main file is also deleted

third, the user function
1, finger: Check user information finger [-s] Username
S: Lists only the user's account number, full name, terminal code and login time
2. CHFN: Set account properties Chfn [-foph] Account
3, ID: Query Uid/gid and other information ID account

Iv. New and deleted user groups (System administrator)
1, Groupadd: Add user group Groupadd [-G GID] [-r] User group name
-G: followed by a specific GID to give directly to a GID
-r: New user Group
2, Groupmod: Modify user group Parameters Groupmod [-G GID] [-n group_name] User group name-G: Modify Gid-n: Modify existing user groups
3. Groupdel: Delete user group Groupdel [user group name]
4, GPASSWD: User group administrator function gpasswd [-A user] GroupName
-A: GroupName master control to face and face users

v. Use of ACLS
1.getfacl: Get ACL Settings item for a file/directory (permission condition)
Getfacl filename
2.setfacl: Set ACL rules for a file/directory
Setfacl [-BKRD] [-m|-x] filename
Eg:setfacl-m G:mygroup:rx doc.txt set up user groups
Eg:setfacl-m u:myuser:rwx doc.txt Setting up users

Six, user identity switch
1, su: simple identity switch su [-LM] [-C command] [username]
2, sudo su input their own account password can switch to the root account exit

vii. User Information transfer on Linux hosts
1, w,who,last,lastlog: query user Information
2, write: User to talk about write user account [user is in the terminal interface]
3, Mail: User email Maill [email protected]-S "Mail title"
If it is sent to the user on the computer, basically even "@localhost" do not have to write
4, Pwck: Check the/ETC/PASSWD account profile information

Linux account management and ACL permissions settings