One, Usermod command 1. Usermod changing a user's properties
Usermod-u 111 User1 Change the UID of user User1 to 111
Usermod-g grp2 user2 Change user2 Group to User2
usermod-d/home/test User3 Change User3 's home directory to/home/test/
Usermod-s/sbin/nologin user2 Change user2 login Shell is not able to log in
2. ID User1
View information such as user Uid,gid, expansion group, etc.
A user can belong to more than one group, with an extension group:
Usermod-g Grp2 user1 Add User1 expansion group to GRP2
[[Email Protected]_46_188_centos ~]# usermod-g grp1,fxq user2[[email protected]_46_188_centos ~]# ID user2uid=1015 ( User2) gid=1017 (user2) groups=1017 (user2), + (FXQ), 1016 (GRP1) [[Email Protected]_46_188_centos ~]#
Second, the user password management 1. change user password:
passwd Root Change root password
passwd fxq change fxq user password
View password file Real storage file/etc/shadow
[[EMAIL PROTECTED]_46_188_CENTOS ~]# CAT /ETC/SHADOWROOT:$1$QOTJNBBE$O3XVX5L0KNPVMXMIVSFNF .:: 0:99999:7:::bin:*:16659:0:99999:7:::d aemon:*:16659:0:99999:7:::adm:*:16659:0:99999:7:::lp:*:16659:0:99999:7 ::: Sync:*:16659:0:99999:7:::shutdown:*:16659:0:99999:7:::halt:*:16659:0:99999:7:::mail:*:16659:0:99999:7:::o Perator:*:16659:0:99999:7:::games:*:16659:0:99999:7:::ftp:*:16659:0:99999:7:::nobody:*:16659:0:99999:7::: avahi-autoipd:!! : 16912::::::systemd-bus-proxy:!! : 16912::::::systemd-network:!! : 16912,:::::d bus:!! : 16912,:::::p olkitd:!! : 16912::::::abrt:!! : 16912::::::libstoragemgmt:!! : 16912::::::tss:!! : 16912::::::ntp:!! : 16912,:::::p ostfix:!! : 16912::::::chrony:!! : 16912::::::sshd:!! : 16912::::::tcpdump:!! : 16912::::::apache:!! : 17296::::::mysql:!! : 17319::::::fxq:$1$ymvfhplx$ixmvlg4chjsxr6ffxtugs1:17322:0:99999:7:::nginx:!! : 17323::::::saslauth:!! : 17344::::::mailnull:!! : 17344::::::smmsp:!! : 17344::::::test:$1$lv1g6wil$gprgn2db1dftlihgc9fbw.:17365:0:99999:7:::zabbix:!! : 17373:0:99999:7::: fxq1:$1$b5o76dkm$sougjjiu7px5avbewrz/o/:17386:0:99999:7:::user2:!! : 17391:0:99999:7:::user3:!! : 17391:0:99999:7:::[[email protected]_46_188_centos ~]#
2. Lock user and Unlock user
At the password! * They are not allowed to log in.
Passwd-l user2 put the user password before adding!!
passwd-u user2 Unlock user password
Usermod-l User2 can also lock the user User2
Usermod-u user2 Unlocking User User2
3. A command in the script changes the password of the user user2:
passwd--stdin user2 change user password
[[Email Protected]_46_188_centos ~]# passwd--stdin user2changing password for user User2.123456passwd:all Authenticatio N Tokens updated successfully. [[Email Protected]_46_188_centos ~]#
[Email Protected]_46_188_centos ~]# echo "qing123." | passwd--stdin user2changing password for user User2.passwd:all authentication tokens updated successfully. [[Email Protected]_46_188_centos ~]#
Echo-e "123\naaa" implements \ n line-break usage
[Email protected]_46_188_centos ~]# echo-e "qing123.\nqing123." | passwd user2changing password for user user2. New Password:retype New Password:passwd:all authentication tokens updated successfully. [[Email Protected]_46_188_centos ~]#
4. Password Security settings:
Greater than 10 bits
Contains numbers, uppercase and lowercase letters, special symbols
cannot be set with regularity
Cannot contain information such as name, birthday, etc.
Iii. mkpasswd Order
MKPASSWD Generate Anytime Password tool: (Make passwd)
If you do not have the MKPASSWD command, install the expect package
Yum Install expect
Options:
-l length number of digits
-s special sign bit number
[Email protected]_46_188_centos ~]# mkpasswd [email protected][[email protected]_46_188_centos ~]# mkpasswd-l 12yme0qzt#3xfe[[email protected]_46_188_centos ~]# mkpasswd-l 12-s 3g\fn%ha2nw7*[[email protected]_46_188_centos ~]# Mkpasswd-l 12-s 08oakipqcnfw3[[email Protected]_46_188_centos ~]#
Mkpasswd-l 12-s 0 Length 12 bits without special symbols
This article is from the "Feng Xiaoqing blog" blog, make sure to keep this source http://fengyunshan911.blog.51cto.com/995251/1956572
Linux usermod, user password management and password random generation tool mkpasswd