Monday, 23 December 2013

Intent of this post is to help the person who are going to attend the basic level of Solaris interview. Few of the User Admin’s related Question and Answers are given below, I hope this will help you to refresh your basic knowledge before attending the interview. Most of the time we very much strong in all components, however basic level of knowledge is one of our key point while attending interview.

User Management Interview Questions:
1. How to create a user ? Brief with full syntax..
/usr/sbin/useradd -u uid -g gid -c " User Descriptions" -m -d "Home Directory Path" -s "Shell" username
Example :
#useradd -u 535 -g unix -c "Unixrock blog" -m -d /export/home/unixrock -s /usr/bin/bash unixrock

OptionsDescription
–u UID ( From 0 to 65535 ) , 0 is reserved for root 
-gPrimary Group 
-mForce to Create Home Directory Specified by –d and copy default skeleton files in /etc/skel folder 
-dUser Home Directory Path 
-c  User Descriptions
-sShell Path

2. What are the important files for User Management task?
/etc/passwd
/etc/shadow
/etc/group
/etc/default/passwd
/etc/default/login

3. Describe the /etc/passwd fields ?
/etc/passwd file is having 7 fields
username:password:uid:gid:comment:home-directory-path:login-shell
Example :
unixrock:x:535:121:Unixrock blog:/export/home/unixrock:/usr/bin/bash

4. Describe the /etc/shadow file fields ?
/etc/shadow file is having 9 fields
loginID:password:lastchg:min:max:warn:inactive:expire:reserved
Example:
unixrock:R1EbI61VDyM2I:15995:7:91:7:::

5. Describe the /etc/group file fields ?
/etc/group file is having 4 fields
groupname:group-pwd:GID:user-list
Example:
unixrock::121:unixrock, raj

6. What is the different between "su  UserID" and "su - UserID" ?
"su UserID"     -  Doesn't check the PATH and Current Working Directory
"su - UserID"   -  Load the User's Profiles  (PATH/Current Working Directory)

7. Default permission of Passwd/Shadow/Group files ?
/etc/passwd 644 
/etc/shadow 644 
/etc/group    400
bash-3.00# ls -ld /etc/passwd /etc/shadow /etc/group
-rw-r--r--   1 root     sys          459 Dec 10 16:32 /etc/group
-rw-r--r--   1 root     sys        18498 Dec 11 09:09 /etc/passwd
-r--------   1 root     sys        10334 Dec 11 09:35 /etc/shadow
bash-3.00#

8. Default permission of file and Directory ?
Default permission of file is 644  (666 - 022 (umask vaule)) 
Default permission of directory is 755  (777 -022 (umask vaule))

9. How to view the list of users who currently logged in the system ?
"who" command will show the users who logged in the current system. 
The command refers /var/adm/utmpx to obtain the information. 
bash-3.00# who
root       pts/2        Sep 10 22:11    (192.168.10.22)
root       pts/3        Dec 11 22:55    (192.168.10.22)
bash-3.00#
bash-3.00# ls -ld /var/adm/utmpx
-rw-r--r--   1 root     bin         2976 Dec 11 22:55 /var/adm/utmpx
bash-3.00# file /var/adm/utmpx
/var/adm/utmpx: data
bash-3.00#

10. How to view the User's login and logout details ?
"last " command will show the users login and logout details.
The command refers /var/adm/wtmpx to obtain the information.
bash-3.00# last
root      pts/3        192.168.10.22    Wed Dec 11 22:55   still logged in
root      sshd         192.168.10.22    Wed Dec 11 22:55   still logged in
root      pts/2        192.168.10.22    Tue Sep 10 22:11   still logged in
root      sshd         192.168.10.22    Tue Sep 10 22:11 - 22:55 (92+00:43)
reboot    system boot                   Tue Sep 10 22:03
reboot    system down                   Fri Sep  6 17:59
wtmp begins Tue Aug 13 01:32
bash-3.00#
bash-3.00# ls -ld /var/adm/wtmpx
-rw-r--r--   1 adm      adm        68820 Dec 11 22:55 /var/adm/wtmpx
bash-3.00# file /var/adm/wtmpx
/var/adm/wtmpx: data
bash-3.00#

11. How to view details information about the User?
"finger username" will show the details about the user.
bash-3.00# finger unixrock
Login name: unixrock
Directory: /home/unixrock               Shell: /bin/sh
Never logged in.
No unread mail
No Plan.
bash-3.00#

12. Describe about SETUID/SETGID/StickyBIT ?
SETUID/SETGID/StickyBIT

13. How to check Primary and Secondary Group of One User ?
"id -a username" will show the user's Primary and Secondary groups.
FYI, One User can be added in 15 no; of Secondary groups, But Only one Primary Group.
bash-3.00# id -a unixrock
uid=100(unixrock) gid=1(other) groups=1(other)
bash-3.00#
gid - Primary Group 
groups - Secondary Group

14. How to rename the existing User ID ?
# usermod -l <newname> <oldname>
bash-3.00# usermod -l unixrock_new unixrock
UX: usermod: unixrock name too long.
bash-3.00# grep -i unixrock /etc/passwd
unixrock_new:x:100:1::/home/unixrock:/bin/sh
bash-3.00#

15. How to lock the User Account ?
# passwd -l UserID
bash-3.00# passwd -s unixrock
unixrock  PS
bash-3.00# passwd -l unixrock
passwd: password information changed for unixrock
bash-3.00# passwd -s unixrock
unixrock  LK
bash-3.00#

16. How to unlock the User Account?

# passwd -u <UserID>
bash-3.00# passwd -s unixrock
unixrock  LK
bash-3.00# passwd -u unixrock
passwd: password information changed for unixrock
bash-3.00# passwd -s unixrock
unixrock  PS
bash-3.00#

17. How to make the user account as non-expriry ?
# passwd -x -1 <userID>
bash-3.00# passwd -s unixrock
unixrock  PS    12/11/13     7    91     7
bash-3.00#
bash-3.00# passwd -x -1 unixrock
passwd: password information changed for unixrock
bash-3.00#
bash-3.00# passwd -s unixrock
unixrock  PS
bash-3.00#

18. How do we set force passwd change for User's first login ?
# passwd -f  <UserID>
bash-3.00# passwd -s unixrock
unixrock  PS    12/11/13     7    91     7
bash-3.00#
bash-3.00# passwd -f unixrock
passwd: password information changed for unixrock
bash-3.00#
bash-3.00# passwd -s unixrock
unixrock  PS    00/00/00     7    91     7
bash-3.00#

19. How to delete the User ID ? 
# userdel <UserID> or # userdel -r <UserID>

-r option will delete the User's Home directory too.

20. Type of SHELLs ? What is initialization file for those SHELLS ?

/bin/bash  - Bourne Again shell
/bin/csh    - C shell
/bin/ksh   - Korn shell
/bin/tcsh   - TC shell
/bin/zsh    - Z shell

Bourne   /etc/profile    $HOME/.profile   /bin/sh     /etc/skel/local.profile
Korn      /etc/profile    $HOME/.profile   /bin/ksh   /etc/skel/local.profile
                                $HOME/.kshrc
C          /etc/.login      $HOME/.cshrc    /bin/csh   /etc/skel/local.cshrc
                                $HOME/.login                   /etc/skell/local.login

21. How to Check the User's Crontabs ? How to allow the User to access the Cron?
# crontab -l <username>
or
# ls -ltr /var/spool/cron/crontabs/

/etc/cron.d/cron.allow  : If the file exists, the users can use crontab whoever listed in that file.

22. How to check User's Present Working Directory Path? How to check the Obsolete Path of running process ?
Find the Present Working Directory Path
# pwd

Find the Obsolete Path of Process.
# pwdx

Advance congrats for your great future. Thank you for reading this post.
Please leave your valuable comment if you have any queries, I will get back to you at earliest.