Linux CentOS7 VMware usermod Command, user password management, mkpasswd command

First, Usermod command

usermod can be used to modify the user account settings

-C,--comment note the new value of the GECOS field
-D,--home Home_dir user's new home directory
-E,--expiredate expire_date set the account expiration date to Expire_date
-F,--inactive inactive expired inactive days, set password to invalid state
-G,--gid group enforces the use of group as the new primary group
-G,--groups groups new list of additional groups groups
-A, the--append group appends the user to the additional group mentioned in-G above,
Do not remove this user from other groups
-H,--help displays this help information and launches
-L,--login login New login Name
-L,--lock lock user account
-M,--move-home move home directory content to a new location (only with-D)
-O,--non-unique allows the use of duplicate (non-unique) UID
-p,--password password set the encrypted password (password) to the new password
-R,--root Chroot_dir CHROOT to the directory
-S,--shell shell the new login shell for the user account
-U,--uid UID user account's new UID
-U,--unlock unlock user account
-Z, new SELinux user mapping for--selinux-user seuser user account

[Email protected] ~]# Usermod-u 111 Uaername
[Email protected] ~]# usermod-g GID username
[Email protected] ~]# usermod-d/home/ss username
[Email protected] ~]# usermod-s/sbin/nologin Usernamer

Add GRP1 into the Davery group

and add User3 into the Daery group.

[Email protected] ~]# usermod-g GRP1 davery
[[email protected] ~]# ID davery
uid=1000 (davery) gid=1003 (GRP1) group =1003 (GRP1)
[Email protected] ~]# usermod-g User3 davery
[[email protected] ~]# ID davery
uid=1000 (davery) gid=1003 (GRP1) group =1003 (GRP1), 1006 (User3)
[Email protected] ~]#

Second, the user password management

change user Password

[Email protected] ~]# passwd
Change the password for the user root.
New Password:
[Email protected] ~]# passwd davery
View User Password

[Email protected] ~]# Head/etc/shadow
Root:$6$6evirlcaxdf9st5r$xz/u82j7ljf.y/rjsrjhmbbwvc8us0r.qkgxmhqx3e3qac2eins.o/pydo6gqsqolopg.av.pi.bajvfiptwp /::0:99999:7:::
Bin:*:17110:0:99999:7:::
Daemon:*:17110:0:99999:7:::
Adm:*:17110:0:99999:7:::
Lp:*:17110:0:99999:7:::
Sync:*:17110:0:99999:7:::
Shutdown:*:17110:0:99999:7:::
Halt:*:17110:0:99999:7:::
Mail:*:17110:0:99999:7:::
Operator:*:17110:0:99999:7:::
[Email protected] ~]#

Lock/unlock user password

[[Email protected] ~] #passwd-L davery

[[Email protected] ~] #passwd-U davery

[Email protected] ~]# usermod-l davery

[Email protected] ~]# usermod-u davery

Set a password for a user

[Email protected] ~]# passwd--stdin davery
Change the password for the user davery.

*******
PASSWD: All the authentication tokens have been successfully updated.

[Email protected] ~]# echo "* * * *" |PASSWD--stdin davery
Change the password for the user davery.
PASSWD: All the authentication tokens have been successfully updated.
[Email protected] ~]#

Extended

[Email protected] ~]# echo-e "123\nsss"
123
Sss
[Email protected] ~]# echo-e "123nsss"
123nsss
[Email protected] ~]# echo-e "123\tsss"
123sss
[Email protected] ~]# echo-e "1233\n1321" |passwd davery
Change the password for the user davery.
[Email protected] ~]#

Third, mkpasswd generate password tool

Automatically generate random passwords

[Email protected] ~]# mkpasswd
-BASH:MKPASSWD: Command not found
[email protected] ~]# Yum install-y expect

...

[Email protected] ~]# mkpasswd
M07grj#oj
[Email protected] ~]# mkpasswd-l 12
gse2e^enuq2l
[Email protected] ~]# mkpasswd-l 12-S4
passwd: Wrong parameter-s4: unknown option
[Email protected] ~]# mkpasswd-l 12-s 4
]ke>;7s^bf0y
[Email protected] ~]#

Linux CentOS7 VMware usermod Command, user password management, mkpasswd command