When you login you get “$” prompt, what is the prompt for root?
Answer: #
2
Explain the difference between grep and egrep?
Answer: Search online
3
What is the port # for DNS, NTP and NFS?
Answer: 53, 123, and 111/2049
4
What is the configuration file name of DNS and where is it located?
Answer: /etc/named.conf
5
How many new directories will be created after running the following command: mkdir {a..c}{1..3}
Answer: 9
6
Your PC is configured with a DNS server address but not the default gateway. Can the PC access internet?
Answer: No
7
What is the difference between IP and Gateway?
Answer: Search online
8
Can you assign one static IP to 2 computers, if not then why?
Answer: No, because it will create an IP conflict
9
How to change IPs address to static?
Answer: ifconfig x.x.x.x
10
You are trying to ping a server by hostname and you get an error message, “ping: unknown host …”. What could be the reason and how to solve the problem so you can ping it by hostname?
Answer: Check /etc/hosts or DNS to see if it has hostname-to-IP entry
11
Explain the difference between relative and absolute path?
Answer: Absolute path starts from / while relative path is from your current directory
12
List 3 different methods of adding user?
Answer: Search online
13
What is the command to change file/directory ownership and group?
Answer: chown and chgrp
14
List any 3 type of filesystem?
Answer: ext4, NTFS, and FAT
15
When you login you get a message on the screen. What is the name of that file and where is it located?
Answer: /etc/motd
16
What is /bin directory used for?
Answer: Search online
17
What are the different types of DNS Server?
Answer: Master and secondary
18
How to change a user password?
Answer: passwd username
19
What is the version of Redhat Linux you have experience with?
Answer: 7.4
20
List any 4 linux distributions?
Answer: Redhat, CentOS, Ubuntu and SUSE
21
How to logoff from the system?
Answer: exit
22
Give any 3 examples of operating systems?
Answer: Windows, Linux and macOS
23
How to create a directory?
Answer: mkdir
24
Where are the zone files located for DNS service?
Answer: /var/named/zonefiles
25
How to check kernel version?
Answer: uname -a
26
Which directory has all the configuration files?
Answer: /etc
27
How to become root user from a regular user?
Answer: su -
28
How many mega bytes in 1 giga bytes?
Answer: Search online
29
What is the purpose of having different network ports?
Answer: So the communication of each application goes through a dedicated port
30
How to display first column of a file?
Answer: cat filename | awk '{print $1}'
31
What is the name of DNS rpm package?
Answer: bind
32
What is the difference between nslookup and dig commands?
Answer: Search online
33
How to check your user id and group id?
Answer: id
34
How to check a file’s permission?
Answer: ls -l
35
What is the difference between “kill” and “kill -9” command?
Answer: Search online
36
What is subnet?
Answer: Search online
37
You are troubleshooting an issue with Redhat support and they have asked you to send the contents of /etc directory. How and which method you will use to transfer the contents?
Answer: Tar (compress) the entire /etc directory and FTP
38
What is root home directory?
Answer: /root
39
What is rsyslogd daemon and its purpose?
Answer: Search online
40
Your company has terminated a server administrator. What is first thing as an administrator you should do to enhance the security?
Answer: Change root password
41
How to check the computer name or host name in Linux?
Answer: hostname
42
Which permission allows a user to run an executable with the permissions of the owner of that file?
Answer: Setuid/setgid (owner execute bit with special permission). Note in original: "First 3 bits should have x"
43
What is the command to untar a tarred file?
Answer: untar (commonly tar -xvf filename.tar)
44
What is /proc directory used for?
Answer: Search online
45
What is the purpose of nsswitch.conf file?
Answer: It tells the system where to go to resolve hostnames
46
List 3 basic commands to navigate the filesystem?
Answer: cd, pwd, and ls
47
Which service/daemon should be running on the server that allows you to connect remotely?
Answer: sshd
48
What is the purpose of firewall?
Answer: Search online
49
List any 3 IT components?
Answer: Hardware, OS and Applications
50
Which directory has all the commands we use, e.g. ls, cd etc.?
Answer: /usr/bin or /bin
51
What is the difference between memory, virtual memory and cache?
Answer: Search online
52
Which of the following is correct?
a. Hardware -> Operating System -> Users
b. Operating System -> Users -> Hardware
c. Database -> Hardware -> Users
Answer: (No explicit answer provided)
53
Which of the following is a communication command?
Options: grep, mail, touch, cd
Answer: mail
54
How to rename a file or directory?
Answer: mv
55
How to change a hostname in Linux?
Answer: Search online
56
How to check network interfaces in Linux?
Answer: ifconfig
57
Why is “tail –f logfilename” command used most often and what does it do?
Answer: It outputs incoming logs in real time
58
What type of hardware have you worked on?
Answer: Get familiar with Dell, HP and UCS hardware (suggested to check vendor websites)
59
How to sort a file in reverse order?
Answer: cat filename | sort -r
60
What is the name of operating system that runs Unix?
Answer: Solaris, HP-UX etc.
61
List all byte sizes from smallest to largest?
Answer: Search online
62
How to check the total number of partition in Linux?
Answer: fdisk -l
63
How to access a linux system from a linux system?
Answer: ssh
64
Explain the procedure of bonding 2 NICs or interfaces together?
Answer: Search online
65
What is the exact command syntax to list the 5th column of a file and cut the first 3 letters?
List 4 commands to display or read a file contents?
Answer: cat, more, less, vi
76
Which command is used to read the top 5 lines of a file?
Answer: head -5 filename
77
What are the different commands or methods to write to a file?
Answer: echo > filename and vi filename
78
What is swap space and how to check swap space?
Answer: Search online
79
What is inode and how to find an inode of a file?
Answer: Search online
80
Which file to edit for kernel tuning?
Answer: Search online
81
What is the latest version of Redhat?
Answer: Search online
82
Name the command to find specific word from a file?
Answer: grep word filename
83
You have scheduled a job using crontab but it does not run at the time you specified, what could be the reason and how would you troubleshoot?
Answer:
Check your system time
Check your crontab entry
Check /var/log/messages
84
How to check system hardware information?
Answer: dmidecode
85
How to check network interface MAC address?
Answer: ifconfig
86
If I don’t want others to read my file1, how to do that?
Answer: Remove r from the last 3 bits of file permission (remove read permission for group/others)
87
What is the purpose of “uniq” and “sed” command?
Answer: Search online
88
Which command is used to list the contents of a directory in the most recent time and in reverse order, meaning the most updated file should be listed on the bottom?
Answer: ls -ltr
89
What is the difference between tar, gzip and gunzip?
Answer: Search online
90
What are the different ways to install an OS?
Answer: DVD, DVD ISO and network boot
91
How to view difference between two files?
Answer: diff file1 file2
92
You noticed that one of the Linux servers has no disk space left, how would you troubleshoot that issue?
Answer:
If running LVM then add more disk and extend LVM
If not running LVM then add more disk, create a new partition and link the new partition to an existing filesystem
93
How to check Redhat version release?
Answer: uname -a or /etc/redhat-release
94
What is the difference between TCP and UDP?
Answer: Search online
95
What is a zombie process?
Answer: Search online
96
How do you search for a pattern/word in a file and then replace it in an entire file?
Answer: sed command
97
Explain the purpose of “touch” command?
Answer: To create an empty file (or update a file's timestamp)
98
If a command hangs, how to stop it and get the prompt back?
Answer: Ctrl+C
99
Which command is used to count words or lines?
Answer: wc
100
How to check the number of users logged in?
Answer: who
101
What is the command to view the calendar of 2011?
Answer: cal 2011
102
Which command is used to view disk space?
Answer: df -h
103
How to create a new group in Linux?
Answer: groupadd
104
What is the command to send a message to everyone who is logged into the system?
Answer: wall
105
Which command is used to check total number of disks?
Answer: fdisk -l
106
What is a mail server record in DNS?
Answer: MX
107
What does the following command line do? ps -ef | awk '{print $1}' | sort | uniq
Answer: Lists the first column (user) of all running processes, sorts them and removes duplicates
108
You get a call that when a user goes to www.yourwebsite.com it fails and gets an error, how do you troubleshoot?
Answer:
Check user's internet connectivity
Check if user's computer has DNS for hostname lookup
Check if the server hosting the website is up
Check if the web service on the server is running
Check DNS availability resolving that website
109
List 4 different directories in /?
Answer: /etc, /bin, /tmp, /home
110
What is the output of the following command: tail -10 filename | head -1
Answer: It shows the first line from the last 10 lines of a file
111
What are the different fields in /etc/passwd file?
Answer: Search online
112
Which command is used to list the processes?
Answer: ps -ef
113
What is the difference between “hostname” and “uname” commands?
Answer: hostname gives the system name and uname gives OS information
114
How to check system load?
Answer: top and uptime
115
How to schedule jobs?
Answer: crontab and at
116
What is the 3rd field when setting up crontab?
Answer: Day of the month
117
What is the command to create a new user?
Answer: useradd
118
What is the “init #” for system reboot?
Answer: 6
119
How to restart a service?
Answer: systemctl restart servicename
120
How to shutdown a system?
Answer: shutdown or init 0
121
What is “ftp” command used for?
Answer: To transfer files from one computer to another
122
Explain cron job syntax? First is minute, second is..?
Answer: Minute, hour, day of the month, month, day of the week and command
123
How to delete a package in Linux?
Answer: rpm -e packagename
124
What is the file name where user password information is saved?
Answer: /etc/shadow
125
Which command you would use to find the location of chmod command?
Answer: which chmod
126
Which command is used to check if the other computer is online?
Answer: ping othercomputer
127
Please explain about LAN, MAN and WAN?
Answer: Search online
128
How to list hidden files in a directory?
Answer: ls -la
129
What is the difference between telnet and ssh?
Answer: ssh is secure whereas telnet is not
130
How to run a calculator on Linux and exit out of it?
Answer: bc and quit
131
List any 4 commands to monitor system?
Answer: top, df -h, iostat, dmesg
132
You are notified that your server is down, list the steps you will take to troubleshoot?
Answer:
Check the system physically
Login through system console
Ping the system
Reboot or boot if possible
133
What is difference between static and DHCP IP?
Answer: Search online
134
How to write in vi editor mode?
Answer: i = insert, a = insert in next space, o = insert in new line
135
What is the difference between “crontab” and “at” jobs?
Answer: crontab is for repetitive jobs while at is for one-time jobs
136
What is vCenter server in VMWare?
Answer: Search online
137
What is “dmidecode” command used for?
Answer: To get system information
138
What is the difference between SAN and NAS?
Answer: Search online
139
What is the location of system logs? E.g. messages
Answer: /var/log directory
140
How to setup an alias and what is it used for?
Answer: alias aliasname="command" — used to create shortcuts for long commands
141
What is the purpose of “netstat” command?
Answer: Search online
142
What are terminal control keys, list any 3?
Answer: Ctrl+C, Ctrl+D and Ctrl+Z
143
Which command(s) you would run if you need to find out how many processes are running on your system?
Answer: ps -ef | wc -l
144
What are the different types of shells?
Answer: sh, bash, ksh, csh, etc.
145
How to delete a line when in vi editor mode?
Answer: dd
146
Which is the core of the operating system?
Options: a) Shell b) Kernel c) Commands d) Script
Answer: Kernel
147
Which among the following interacts directly with system hardware?
Options: a) Shell b) Commands c) Kernel d) Applications
Answer: Kernel
148
How to save and quit from vi editor?
Answer: Shift+ZZ or :wq!
149
What is the difference between a process and daemon?
Answer: Search online
150
What is the process or daemon name for NTP?
Answer: ntpd
151
What are a few commands you would run if your system is running slow?
Answer: top, iostat, df -h, netstat, etc.
152
How to install a package in Redhat Linux?
Answer: yum install packagename
153
What is the difference between “ifconfig” and “ipconfig” commands?
Answer: ifconfig for Linux and ipconfig for Windows
154
What is the first line written in a shell script?
Answer: Define shell, e.g. #!/bin/bash
155
Where is the network (Ethernet) file located, please provide exact directory location and file name?
Answer: /etc/sysconfig/network-scripts/ifcfg-nic
156
Why do we use “last” command?
Answer: To see who has logged into the system whether active or logged off
157
What does RHEL Linux stand for?
Answer: Search online
158
To view your command history, which command is used and how to run a specific command?
Answer: history and !# (use history number to run a specific command)
159
What is NTP and briefly explain how does it work and where is the config files and related commands of NTP?
Answer: Search online
160
How to disable firewall in Linux?
Answer: Search online
161
How to configure mail server relay for sendmail service?
Answer: Edit /etc/mail/sendmail.mc and add SMART_HOST entry
162
Where is samba log file located?
Answer: /var/log/samba
163
What is mkfs command used for?
Answer: To create a new filesystem
164
If you create a new group, which file does it get created in?
Answer: /etc/group
165
Which file has DNS server information (e.g. DNS resolution)?
Answer: /etc/resolv.conf
166
What are the commands you would run if you need to find out the version and build date of a package (e.g. http)?
Answer: rpm -qi http
167
On the file permissions? What are the first 3 bits for and who is it for?
Answer: Read, write and execute for the owner of the file
168
How to create a soft link?
Answer: ln -s
169
How to write a script to delete messages in a log file older than 30 days automatically?
Answer: Search online
170
How to quit out of “man” command?
Answer: q
171
Which command is used to partition disk in Linux?
Answer: fdisk
172
What is the difference between “shutdown” and “halt” command?
Answer: Search online
173
What is the exact syntax of mounting NFS share on a client and also how to un-mount?
Answer: Search online
174
What experience do you have with scripting, explain?
Answer: if-then, do-while, case, for loop scripts
175
How to get information on all the packages installed on the system?
Answer: rpm -qa
176
Explain VMWare?
Answer: Search online
177
You are tasked to examine a log file in order to find out why a particular application keep crashing. Log file is very lengthy, which command can you use to simplify the log search using a search string?
Answer: Use grep for error, warning, failure etc. in /var/log/messages file
178
What is /etc/fstab file and explain each column of this file?
Answer: Search online
179
What the latest version of Windows server?
Answer: Search online
180
What is the exact command to list only the first 2 lines of history output?
Answer: history | head -2
181
How to upgrade Linux from 7.3 to 7.4?
Answer: yum install update
182
How to tell which shell you are in or running?
Answer: $0
183
You have tried to “cd” into a directory but you have been denied. You are not the owner of that directory, what permissions do you need and where?
Answer: Execute (x) permission on directory (and read if listing) — original mentions "r – x" for last bits
184
What is CNAME record in DNS?
Answer: Entry for hostname to hostname
185
What is the name of VMWare operating system?
Answer: ESXi
186
What is the client name used to connect to ESXi or vCenter server?
Answer: vSphere client
187
You get a call from a user saying that I cannot write to a file because it says, permission denied. The file is owned by that user, how do you troubleshoot?
Answer: Give write permission on the owner bits (first 3 bits)
188
What is the latest version of VMWare?
Answer: Search online
189
What is the name of firewall daemon in Linux?
Answer: firewalld
190
Which command syntax you can use to list only the 20th line of a file?
Answer: Search online
191
What is the difference between run level 3 and 5?
Answer: 3 = Boot system with networking, 5 = Boot system with networking and GUI
192
List a few commands that are used in troubleshooting network related issue?
Answer: netstat, tcpdump, etc.
193
What is the difference between domain and nameserver?
Answer: Search online
194
You open up a file and it has 3000 lines and it scrolled up really fast, which command you will use to view it one page at a time?
Answer: more or less
195
How to start a new shell. E.g. start a new ksh shell?
Answer: Type ksh or bash
196
How to kill a process?
Answer: kill processID
197
How to check scheduled jobs?
Answer: crontab -l
198
How to check system memory and CPU usage?
Answer: free and top
199
Which utility could you use to repair the corrupted file system?
Answer: fsck
200
What is the command to make a service start at boot?
Answer: systemctl enable servicename
201
How to combine 2 files into 1? E.g. you have 3 lines in file “A” and 5 lines in file “B”, which command syntax to use that will combine into one file of 3+5 = 8 lines
Answer: cat fileA >> fileB
202
What is echo command used for?
Answer: To output to the screen
203
What does the following command do? echo This year the summer will be great > file1
Answer: It creates a new file file1 with the content "This year the summer will be great"
204
Which file to modify to allow users to run root commands?
Answer: /etc/sudoers
205
You need to modify httpd.conf file but you cannot find it, Which command line tool you can use to find file?
Answer: find / -name "httpd.conf"
206
Your system crashed and being restarted, but a message appears, indicating that the operating system cannot be found. What is the most likely cause of the problem?
