(B15) Linux Admin part4 User Management -2-Useradd,Groupadd,Usermod,Userdel
20220322 113918
to add user
useradd user1
passwd user1
id user1
/etc/passwd
/etc/group
/etc/shadow
*every user must be in a Primary group
*uid,gid,home directory, password,login shell
user1 -Primary Group- user1
-----------------
groupadd group1
groupadd -g 1200 group2
useradd -g group1 user2
useradd -g group2 user3
useradd -g 1200 user4
user2 --Pg-- group1
user3,user4 --Pg-- group2
*user2,user3,user4 groups wont created by default
--------------------
cat /etc/passwd
student15a:x:1000:1000:student15a:/home/student15a:/bin/bash
username uid gid comment home directory login shell
------------------------
?
?how to add a user
useradd u1
?password user
passwd u1
?id u1
uid:u1-1010 gid:u1-1010
?add group
groupadd g1
?useradd -g g1 u2
useradd -g g1 u3
useradd -g g1 u4
------------------------------------------------------------------
create a user name: user5, uid:1010, Pg:group2, Sg:group1, home dir:/home/user5data
useradd -u 1010 -g 1200 -G group1 -d /home/user5data -s /bin/bash user5
tail -3 /etc/passwd
user3:x:1007:1200::/home/user3:/bin/bash
user4:x:1008:1200::/home/user4:/bin/bash
user5:x:1010:1200::/home/user5data:/bin/bash
id user5
uid=1010(user5) gid=1200(group2) groups=1200(group2),1006(group1)
ls -l /home
drwx------. 3 user3 group2 78 Mar 22 11:53 user3
drwx------. 3 user4 group2 78 Mar 22 11:54 user4
drwx------. 3 user5 group2 78 Mar 22 12:07 user5data
------------------------------------------------------------
modify user
usermod -
-l -u -g -c -d -s
student15a:x:1000:1000:student15a:/home/student15a:/bin/bash
username uid gid comment home directory login shell
usermod
-u -uid
-g -gid/primary group
-l -login name
-G -supplementry/secondary
-d -home directory
-c -comment
-a -append
-U -unlock
-L -Lock
-s -login shell
-p -password xx
-e
-f
usermod --help
useradd --help
tail /etc/passwd
student15a:x:1000:1000:student15a:/home/student15a:/bin/bash
dheeraj:x:1001:1001::/home/dheeraj:/bin/bash
gayatri:x:1002:1002::/home/gayatri:/bin/bash
usermod -c "Gayatri Nirmal" gayatri
tail /etc/passwd
student15a:x:1000:1000:student15a:/home/student15a:/bin/bash
dheeraj:x:1001:1001::/home/dheeraj:/bin/bash
gayatri:x:1002:1002:Gayatri Nirmal:/home/gayatri:/bin/bash
----------------
id gayatri
uid=1002(gayatri) gid=1002(gayatri) groups=1002(gayatri)
-add gayatri to B15 group as secondary/supplimaentry group
usermod -G B15 gayatri
id gayatri
uid=1002(gayatri) gid=1002(gayatri) groups=1002(gayatri),1003(B15)
-----------------
delete a user
userdel --deletes user but not user's personal data(home dir)
userdel -r --deletes user along with user's personal data(home dir)
ls -l /home
drwx------. 3 user3 group2 78 Mar 22 11:53 user3
drwx------. 3 user4 group2 78 Mar 22 11:54 user4
drwx------. 3 user5 group2 78 Mar 22 12:07 user5data
tail /etc/passwd
user3:x:1007:1200::/home/user3:/bin/bash
user4:x:1008:1200::/home/user4:/bin/bash
user5:x:1010:1200::/home/user5data:/bin/bash
userdel user5
tail /etc/passwd
user3:x:1007:1200::/home/user3:/bin/bash
user4:x:1008:1200::/home/user4:/bin/bash
id user5
id: user5: no such user
ls -l /home
drwx------. 3 user4 group2 78 Mar 22 11:54 user4
drwx------. 3 1010 group2 78 Mar 22 12:07 user5data
id user4
uid=1008(user4) gid=1200(group2) groups=1200(group2)
tail /etc/passwd
user4:x:1008:1200::/home/user4:/bin/bash
userdel -r user4
tail /etc/passwd
user3:x:1007:1200::/home/user3:/bin/bash
id user4
id: user4: no such user
ls -l /home
drwx------. 3 user2 group1 78 Mar 22 11:53 user2
drwx------. 3 user3 group2 78 Mar 22 11:53 user3
drwx------. 3 1010 group2 78 Mar 22 12:07 user5data
----------
ls -l /home
drwx------. 3 user2 group1 78 Mar 22 11:53 user2
drwx------. 3 user3 group2 78 Mar 22 11:53 user3
drwx------. 3 1010 group2 78 Mar 22 12:07 user5data
rmdir /home/user5data
rmdir: failed to remove ‘/home/user5data’: Directory not empty
ls /home/user5data
ls -a /home/user5data
. .. .bash_logout .bash_profile .bashrc .mozilla
rm -r /home/user5data
rm: descend into directory ‘/home/user5data’? ^C
rm -rf /home/user5data
ls /home/user5data
ls: cannot access /home/user5data: No such file or directory
ls /home/
user2
user1 user3
-----
tail /etc/passwd
id chennareddy
ls -l /home
usermod -l chenna chennareddy
tail /etc/passwd
id chennareddy
id chenna
ls -l /home
usermod -d /home/chenna chenna
ls -l /home
tail /etc/passwd
ls -l /home
mv chennareddy chenna
mv /home/chennareddy /home/chenna
ls -l /home
----
Watch video (B15) Linux Admin part4 User Management -2-Useradd,Groupadd,Usermod,Userdel online without registration, duration 01 hours 11 minute 03 second in high hd quality. This video was added by user Latif Shaik 22 March 2022, don't forget to share it with your friends and acquaintances, it has been viewed on our site 35 once and liked it 0 people.