Top 165 Unix Multiple Choice Questions (MCQs) with Answers

1 .

What is Unix?

A)

Unix is a text editor

B)

Unix is a software program

C)

Unix is an operating system

D)

Unix is a programming language

Correct Answer : Unix is an operating system

Explanation : Unix is an operating system developed in the early 1970’s at Bell Labs by Dennis Ritchie, Ken Thompson, and others. It is a multiuser, multitasking and timesharing operating system. The power of Unix is derived from its commands and their multiple options.

2 .

The Unix shell is both _______ and _______ language.

A)

scripting, interpreter

B)

high level, low level

C)

interpreter, executing

D)

interactive, responsive

Correct Answer : scripting, interpreter

Explanation : The UNIX shell is both an interpreter and scripting language. We can also say that shell can be interactive or non-interactive. When we log in to our system, interactive shell presents a prompt and wait for our requests while a non-interactive shell is managed by an interactive shell while executing a shell script.

3 .

Which symbol will be used with grep command to match the pattern pat at the beginning of a line?

A)

pat^

B)

^pat

C)

$pat

D)

pat$

Correct Answer : ^pat

4 .

Which command is used to change protection mode of files starting with the string emp and ending with 1,2, or 3?

A)

chmod 777 emp*

B)

chmod 222 emp?

C)

chmod u+r ??? emp

D)

chmod u+x emp[1-3]

Correct Answer : chmod u+x emp[1-3]

5 .

Which command is used to copy all files having the string chap and any two characters after that to the progs directory?

A)

cp chap* progs

B)

cp chap?? progs

C)

cp chap?? /progs/*

D)

cp chap[12] /progs/*.*

Correct Answer : cp chap?? progs

6 .

Which command is used to sort the lines of data in a file in reverse order

A)

sh

B)

st

C)

sort

D)

sort -r

Correct Answer : sort -r

7 .

Which command is used to display the top of the file?

A)

cat

B)

grep

C)

head

D)

more

Correct Answer : head

Explanation : The head command displays the first few lines at the top of a file. It can be useful when you want a quick peek at a large file, as an alternative to opening the file.

8 .

Which of the following files contains information related to password aging?

A)

Profile

B)

Shadow

C)

Password

D)

All of the above

Correct Answer : Password

9 .

Which command will be used with vi editor to replace text from cursor to right?

A)

r

B)

R

C)

s

D)

S

Correct Answer : R

10 .

Which of the following commands is used to rename a file?

A)

mv

B)

ren

C)

remove

D)

rename

Correct Answer : mv

11 .

Which of the following commands is used to copy a file wb from the programs directory into a file called wbx in the misc directory?

A)

tar programs/wb misc/wbx

B)

copy programs/wb misc/wbx

C)

copy a:programs/wb b:misc/wbx

D)

cp programs/wb misc/wbx

Correct Answer : cp programs/wb misc/wbx

12 .

In which language UNIX is written?

A)

C

B)

C++

C)

Java

D)

Python

Correct Answer : C

Explanation : UNIX was originally written in Assembly language but Dennis Ritchie and Ken Thompson wanted an operating system which could run on more than one type of hardware.

So in 1973, they rewrote the whole operating system in C language due to which one of the strongest features i.e. portability was added to the operating system.

13 .

Which of the following is the first UNIX editor?

A)

emacs

B)

vi

C)

ex

D)

ed

Correct Answer : ed

Explanation : The first editor that was used in UNIX systems was ‘ed’. The main reason behind the replacement of ‘ed’ was that it can only edit files in the current directory and cannot execute shell commands.

14 .

Which of the following is not a feature of Unix?

A)

multiuser

B)

portability

C)

easy to use

D)

multitasking

Correct Answer : easy to use

Explanation : UNIX is a multitasking operating system i.e. a user can run multiple tasks concurrently. Similarly, it is a multiuser system because it permits working with multiple users on a single operating system. But a major disadvantage of UNIX lies in the fact that the richness provided by its commands requires a special type of commitment to understand the subject. i.e. the user must be well aware of commands he is using and the functions performed by them.

15 .

The File that contains a set of instructions which are performed when a user logs in, is

A)

.exrc

B)

.profile

C)

.autoexec

D)

autoexec.bat

Correct Answer : .profile

16 .

The octal representation 652 indicates

A)

Write permission for others

B)

Execute permission for the owner

C)

Read and write permission of groups

D)

All of the above

Correct Answer : Write permission for others

17 .

Which of the following command is used to count just the number of lines contained in a file?

A)

wc -c

B)

wc -l

C)

wc -r

D)

wc -w

Correct Answer : wc -l

18 .

Which of the following command is used to go to home directory?

A)

cd

B)

cd/

C)

cd..

D)

cd HOME.

Correct Answer : cd

19 .

Which command is used to move all files to the bin sub-directory of the parent directory?

A)

mv * /bin/*

B)

mv *.* /bin/

C)

mv * ../bin

D)

mv * ../bin *.*

Correct Answer : mv * ../bin

20 .

Which command is used to remove a directory?

A)

rd

B)

rdir

C)

dldir

D)

rmdir

Correct Answer : rmdir

21 .

Which of the following keys is used to replace a single character with new text?

A)

s

B)

S

C)

r

D)

C

Correct Answer : s

22 .

Which command is used to extract specific columns from the file?

A)

cat

B)

cut

C)

grep

D)

paste

Correct Answer : cut

23 .

Which command sends the word count of the file infile to the newfile.

A)

wc infile - newfile

B)

wc infile >newfile

C)

wc newfile

D)

wc infile | newfile

Correct Answer : wc infile >newfile

24 .

Which command is used to remove the read permission of the file 'note' from both the group and others?

A)

chmod go-x note

B)

chmod go+r note

C)

chmod go-r note

D)

chmod go+rw note

Correct Answer : chmod go-r note

25 .

Which command is used to list all the files with extension .lst?

A)

ls *.*

B)

ls lst*

C)

ls *[lst]

D)

ls -l *.lst

Correct Answer : ls -l *.lst

26 .

Which option is used with the chmod command recursively to all files and sub-directories in a directory?

A)

-R

B)

-x

C)

-i

D)

-1

Correct Answer : -R

27 .

Which command is used to change directory to the name beginning with a 'p'?

A)

cd p

B)

cd p?

C)

cd p*

D)

cd [p]

Correct Answer : cd p*

28 .

Which commands is used to assign executable permission to all of the files named "letter"?

A)

chmod u+x letter

B)

chmod ugo+x letter

C)

chmod ugo+r letter

D)

chmod ugo+rw letter

Correct Answer : chmod ugo+x letter

29 .

Which of the following is not true about Unix?

A)

UNIX was not written in â€˜Câ€™ language

B)

Linux is also known as a version of UNIX

C)

A user can run multiple programs at the same time; hence UNIX is called a multitasking environment

D)

Many people can use a UNIX based computer at the same time; hence UNIX is called as a multiuser system

Correct Answer : UNIX was not written in â€˜Câ€™ language

Explanation : One of the most attractive features of UNIX is that it supports multi-user and multitasking environment which makes it so popular among its users. There are many UNIX variants available in the market. Solaris Unix, AIX, HP Unix, BSD are some of the examples. Linux is also a flavor of UNIX which is freely available. Unix was developed in 1969 by AT&T employees Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna at Bell Labs and was written in ‘C’.

30 .

Which editor is used by the Unix system to edit files?

A)

vi

B)

word

C)

notepad

D)

notepad++

Correct Answer : vi

Explanation : It doesn’t matter what kind of work we are doing on a UNIX system, we always need an editor to edit some system files or ordinary files. For this purpose, vi editor is used in UNIX. Currently, vim (vi improved) is an improved version which is supported by LINUX systems.

31 .

Which of the following is not a part of all the versions of Unix?

A)

System Calls

B)

Kernel and Shell

C)

Commands and utilities

D)

Graphical user interface

Correct Answer : Graphical user interface

Explanation : The kernel is the heart of the operating system while the shell is the utility which processes our requests. While system calls are a handful of functions which are used to interact with the kernel and make available the services provided by the operating system. A Graphical user interface (GUI) is available in UNIX, but the traditional UNIX interface is the command line only.

32 .

Which part of the Unix operating system interacts with the hardware?

A)

Shell

B)

Vi editor

C)

Kernel

D)

Application program

Correct Answer : Kernel

Explanation : The kernel is the core of the operating system. It is a collection of routines written in C which directly communicates with the hardware. User programs that need to interact with the hardware access the services of the kernel. There is only one kernel running on a system, unlike shells which can be multiple.

33 .

Which command is used to display the documentation of commands in Unix?

A)

man

B)

help

C)

search

D)

whatis

Correct Answer : man

Explanation : UNIX provides us with a facility of man command, which is used for getting documentation of any command. For example, to seek help on wc command simply type man wc. This will simply display all the possible operations, options, description, synopsis of wc command. The POSIX specification requires only one available option with man command i.e. -k, which prints a one-line description of the command. whatis command is also available on many UNIX systems which also displays a one-line description of the command. man -f emulates the behavior of whatis command.

34 .

Which Unix command is used for changing the current directory?

A)

cp

B)

cd

C)

rm

D)

pwd

Correct Answer : cd

Explanation : cd (change directory) command is used for moving around the file system. cd command is usually invoked with a argument. After invocation, it changes the current directory to the directory specified as argument. Cp command is used for copying files while rm command is used for deleting files.

For example: our current directory is /bin/user06 and we want to change our directory to a directory named dir_one which is inside the user06 directory. To do so, type the following:

$ cd dir_one
$pwd
/bin/user06/dir_oneâ€‹

35 .

Which command is used to save the standard output in a file, as well as display it on the terminal?

A)

cat

B)

tee

C)

grep

D)

more

Correct Answer : tee

36 .

The command that can be used to restrict incoming messages to a user is

A)

halt

B)

grep

C)

mesg

D)

sleep

Correct Answer : mesg

37 .

Which of the following commands is used to copy directory structures in and out

A)

cp

B)

copy

C)

cp - p

D)

cpio

Correct Answer : cpio

38 .

Which of following commands is used for an automatic reminder service?

A)

mail

B)

write

C)

mesg

D)

calendar

Correct Answer : calendar

39 .

Which command allows you to view your file 24 lines at a time?

A)

pg

B)

lp

C)

cat

D)

more

Correct Answer : pg

40 .

Which of the following commands is used to display the directory attributes rather than its contents?

A)

ls -F

B)

ls -l

C)

ls -x

D)

ls -l -d

Correct Answer : ls -l -d

41 .

Which of the following files will displayed by this command cat *ch*

A)

.ch

B)

catch

C)

patch

D)

All of the above

Correct Answer : All of the above

42 .

The Octal number to be given alogn with chmod command to make a file readable, writable and executable to the owner, readable and executable to group and others is:

A)

755

B)

744

C)

555

D)

000

Correct Answer : 755

43 .

If you are to use [Control-c] as the interrupt key instead of [Del], then you will have to use

A)

tty ^c

B)

stty intr \^c

C)

stty echoe

D)

stty echo \^a

Correct Answer : stty intr \^c

44 .

Which of the following is not a communication command.

A)

grep

B)

mail

C)

mesg

D)

write

Correct Answer : grep

45 .

Which set option is used with vi editor to display line numbers on screen?

A)

liv

B)

ic

C)

nu

D)

nm

Correct Answer : nu

46 .

Which command is used to print a file?

A)

lp

B)

pg

C)

prn

D)

print

Correct Answer : lp

47 .

Which command will be used with vi editor to replace single character under cursor with any number of characters?

A)

S

B)

s

C)

a

D)

i

Correct Answer : s

48 .

Which of the following set options is used with vi editor to ignore case while searching for patterns?

A)

ai

B)

ts

C)

sm

D)

ic

Correct Answer : ic

49 .

Which command is used to list out all the hidden files along with the other files?

A)

ls -l

B)

ls -x

C)

ls -a

D)

ls -F

Correct Answer : ls -a

50 .

Which command is used for printing the current working directory?

A)

pwd

B)

cd

C)

dir

D)

HOME

Correct Answer : pwd

Explanation : pwd command is used for checking our current directory. Current directory is the directory in which we are currently working. pwd displays the absolute pathname i.e. with respect to the root directory.

$ pwd
/home/user06/Abdullahâ€‹

51 .

Which command is used for listing files in a directory?

A)

ps

B)

ls

C)

wc

D)

list

Correct Answer : ls

Explanation : ls command is one of the most powerful commands used in UNIX system. It comes available with a bunch of options for listing files available in the directory. There are a number of options like -l, -a which are used for listing files in different manners according to user’s need.

$ ls
001.sh        
FILE2       
abc.txt
dir08â€‹

52 .

Which command is used by the user to change their login password in Unix?

A)

cp

B)

man

C)

reset

D)

passwd

Correct Answer : passwd

Explanation : Since UNIX is a multiuser system, it requires a password from every user who wants to log in to the system to help ensure that all the data and files of the user are secure from hackers and errant users. A user can simply change his/her login password by using the passwd command. Simply type this command on the terminal and then enter the old password, which after successful verification would allow the user to input a new password for his login.

53 .

Which command is used for displaying the contents of a file in Unix?

A)

cp

B)

rm

C)

cat

D)

mkdir

Correct Answer : cat

Explanation : cat command is used to display the contents of a file. For displaying the contents, simply invoke the cat command with the filename (whose contents are to be displayed) as an argument. For example, if abd.txt file contains “HELLO WORLD” then,

$ cat abd.txt
HELLO WORLDâ€‹

54 .

Which command is used to compress files?

A)

gzip

B)

cmp

C)

comm

D)

gunzip

Correct Answer : gzip

Explanation : To conserve disk space we need to compress a file. gzip is a very popular program used with one or more filenames for compression.

$ gzip  file01.txtâ€‹

55 .

Which command is used for displaying the beginning of a file in Unix?

A)

lp

B)

pr

C)

head

D)

begin

Correct Answer : head

Explanation : The head command is used for displaying the top of the file. As the name suggests, it displays the beginning of the file which is specified as an argument to the command. For example,

$ head emp.lstâ€‹

56 .

Which of the following special shell variables is used to process number of the current shell?

A)

$*

B)

$$

C)

$!

D)

$0

Correct Answer : $$

57 .

Which option is used with cmp command to give a detailed list of the byte number and the differing bytes in octal for each character that differs in both the files?

A)

-b

B)

-d

C)

-r

D)

-l

Correct Answer : -l

58 .

Which command is used with vi editor scroll half page backward?

A)

[Control-c]

B)

[Control-d]

C)

[Control -P]

D)

[Control - u]

Correct Answer : [Control - u]

59 .

Which command is used with vi editor to move cursor forward to first occurrence of character 'ch' in the current line?

A)

ech

B)

fch

C)

tch

D)

rch

Correct Answer : fch

60 .

Which of the following keys is used to delete the character beneath the cursor?

A)

x

B)

X

C)

D

D)

dd

Correct Answer : x

61 .

Which of the following keys is used to move the cursor to the end of the paragraph.

A)

|

B)

{

C)

}

D)

$

Correct Answer : }

62 .

Which command is used to concatenate all files beginning with the string 'emp' and followed by a non-numeric characters?

A)

cat emp[a-z]

B)

cat emp[x-z]

C)

cat emp[!0-9]

D)

more [emp][!0-9]

Correct Answer : cat emp[!0-9]

63 .

The command which transcribes the standard input to the standard output and also makes a copy of the same in a file is

A)

tr

B)

tee

C)

sort

D)

grep

Correct Answer : tee

Explanation : The tee command reads standard input, then writes its content to standard output and simultaneously copies it into the specified file(s) or variables.

64 .

Which command is used to remove a file?

A)

rm

B)

mv

C)

del

D)

remove

Correct Answer : rm

65 .

Which symbol is used to separate more than one command in the same command line?

A)

:

B)

#

C)

$

D)

;

Correct Answer : ;

66 .

Which of the following commands is used to absolutely assign all permissions to the owner, read and write permissions to the group and only executable permission to the others of the file note?

A)

chmod 761 note

B)

chmod 671 note

C)

chmod 167 note

D)

chmod 4=rwx, g=rw note

Correct Answer : chmod 761 note

67 .

The chmod ugo+rw note command can be represented in octal notation as

A)

chmod 333 note

B)

chmod 444 note

C)

chmod 666 note

D)

chmod 555 note

Correct Answer : chmod 666 note

68 .

Which of the following commands is used to display the filenames in multiple columns with indication of directories and executable file?

A)

Ip

B)

ls -F -x

C)

ls -l

D)

ls ~ x

Correct Answer : ls -F -x

69 .

Which command is used with vi editor to search a pattern in the forward direction?

A)

/

B)

?

C)

//

D)

??

Correct Answer : /

70 .

Which of the following commands is used to assign executable permission to the owner of the file named "note"?

A)

chmod g+x note

B)

chmod u+x note

C)

chmod u+w note

D)

chmod ugo+x note

Correct Answer : chmod u+x note

Explanation : Users selection :

u - user: the owner of the file.
g - group: users who are members of the file's group.
o - others: users who are not the owner of the file or members of the group.
a - all: all three of the above, is the same as ugo.

Permissions :

r - read
w - write
x - execute

So, u+x => Execute (x) permission to Owner (u).

71 .

Which symbol is used with the tail command to print the file from the selected line?

A)

â€“

B)

^

C)

%%

D)

+

Correct Answer : +

Explanation : We can also address lines from the beginning instead of the end. The +count option allows us to do that, where count represents the line number from where the selection should begin. For example,

$ tail +11 emp.lst        // start printing from 11th line onwardsâ€‹

72 .

echo command is used for ______

A)

displaying diagnostic messages

B)

displaying errors

C)

displaying date and time

D)

displaying operating system details

Correct Answer : displaying diagnostic messages

Explanation : echo command is generally used for displaying diagnostic messages on to the terminal or to issue prompt for reading the user input. All shells now have echo built in i.e. it is an internal command.

$ echo hello
helloâ€‹

73 .

What is the function of cp command in Unix?

A)

delete a given file

B)

change the directory

C)

list all the available files in the current directory

D)

cp is a command used for copying files and directories

Correct Answer : cp is a command used for copying files and directories

Explanation : cp command is basically used for creating a copy of source file or a group of files. The syntax of the command requires at least two filenames to be specified. If both the files specified are ordinary files, the first file will be copied to the second file. The syntax of cp command is cp source_filename destination_filename. The contents of the source file will be copied to the destination file in the same directory.

$ cp  file_01  file_02               // copies file_01 to file_02â€‹

74 .

Which command is used for renaming files in Unix?

A)

cp

B)

move

C)

mv

D)

rename

Correct Answer : mv

Explanation : mv command is used for renaming files. This command does not create a copy of the file, it simply renames it. To rename file1 to file2 simply type,

$ mv  file1  file2â€‹

75 .

Which command is used for comparing two files?

A)

diff

B)

cmp

C)

comp

D)

comm

Correct Answer : cmp

Explanation : cmp command is used for comparing two files byte by byte. It displays the first mismatch and its location on the terminal. It does not bother about subsequent mismatches but displays only the first mismatch. As soon as the first difference is found, the command terminates and outputs the line and byte in which there is a difference. For example,

$ cmp  file01  file02
file01  file02 differ: Byte 20, Line 2â€‹

diff command is used for converting one file into another in order to make them identical and comm is used for displaying the common elements in both the files.

76 .

Which Unix command is used for counting words, lines, and characters in a file?

A)

wc

B)

diff

C)

man

D)

count

Correct Answer : wc

Explanation : UNIX provides a universal word counting program that allows us to count the number of words, lines and characters in a file. It takes a filename as an argument as produces a 4 column output.

$ wc file01
3   9   45  file01â€‹

Above output indicates that file01 contains 3 lines, 9 words and 45 characters.

77 .

In UNIX, which command is used to change the permissions of a file?

A)

ch

B)

chgrp

C)

chown

D)

chmod

Correct Answer : chmod

Explanation : The chmod (change mode) command is used to change the permissions of files. This command can only be run by the owner of the file or by the super user.

78 .

Which command is used to assign only read permission to all three categories of the file 'note'?

A)

chmod a-rw

B)

chmod go+r note

C)

chmod ugo=r note

D)

chmod u+r,g+r,o-x note

Correct Answer : chmod ugo=r note

79 .

Which command will be used with vi editor to append text at end of line?

A)

A

B)

a

C)

I

D)

i

Correct Answer : A

80 .

The first set of the three permissions (rw) pertains to the owner of the file, indicating that the owner has

A)

executable permission only

B)

both read and write permissions

C)

write and executable permissions

D)

both read and executable permissions.

Correct Answer : both read and write permissions

81 .

Which of the following commands is used to save the output of the who command in a file named user.lst, as well as display it?

A)

who > user.lst

B)

who < user.lste

C)

who >> user.lst

D)

who | tee user.lst

Correct Answer : who | tee user.lst

82 .

Which of the following shell's wildcards are used to match any number of characters including none?

A)

*

B)

?

C)

[ijk]

D)

[!ijk]

Correct Answer : *

83 .

The agency that sits between the user and the UNIX system is called the

A)

erxc

B)

logic

C)

profile

D)

shell

Correct Answer : shell

84 .

Which of the following commands is used to update access and modification times of a file?

A)

cat

B)

wc

C)

grep

D)

touch

Correct Answer : touch

85 .

Which command is used to count just the number of characters in a file?

A)

wc -r

B)

wc -w

C)

wc -c

D)

wc - 1

Correct Answer : wc -c

86 .

Which of the following commands is used to list contents of directories?

A)

lp

B)

ls

C)

dir

D)

tar

Correct Answer : ls

87 .

Which command is used to display a file contents in octal form?

A)

od

B)

cd

C)

of

D)

oct

Correct Answer : od

88 .

The command to count the number of files in the current directory by using pipes, is

A)

ls | wc

B)

ls | ws -c

C)

ls | wc -w

D)

ls -l | wc -l

Correct Answer : ls | wc -w

89 .

Which of the following commands is used to get directory one level up?

A)

cd

B)

cd ..

C)

cd/

D)

chdir

Correct Answer : cd ..

90 .

Which command is used to delete all files in the current directory as well as all files and sub-directories in its subdirectories?

A)

rm *

B)

rm *.*

C)

rm all

D)

rm -r *

Correct Answer : rm -r *

91 .

Which of the following commands is used to change the working directory?

A)

cd

B)

cdir

C)

chdir

D)

changedir

Correct Answer : cd

92 .

Which symbol is used to change permissions for hidden files in Unix?

A)

.

B)

*

C)

$

D)

&

Correct Answer : .

Explanation : To change permissions for hidden files, use the (.) symbol with chmod command.

$ chmod 755  .    // works on hidden filesâ€‹

93 .

Which command is used for saving and quitting the vi editor simultaneously?

A)

:f

B)

:q

C)

:w

D)

â€˜:xâ€™

Correct Answer : â€˜:xâ€™

Explanation : ‘:x’ command saves our content and quits the editor simultaneously. This command is invoked in ex-mode.

94 .

How can we escape to the UNIX shell without quitting vi editor?

A)

using ctrl-D

B)

using ctrl-Z

C)

using â€˜:shâ€™ command and using ctrl-Z

D)

using â€˜:shâ€™ command

Correct Answer : using â€˜:shâ€™ command and using ctrl-Z

Explanation : We can escape to the shell without quitting the editor using ‘:sh’ command or ctrl-Z. Sometimes it is necessary to return to shell prompt to execute a UNIX command or compile our program. For this purpose, we use these commands.

95 .

For creating and removing directories, which of the following system calls are used?

A)

chdir and chown

B)

mkdir and chdir

C)

mkdir and rmdir

D)

rmdir and chown

Correct Answer : mkdir and chdir

Explanation : A non privileged user uses mkdir and rmdir calls for creating and removing directories respectively.

96 .

The command used to remove the directory is;

A)

rd

B)

rdir

C)

remove

D)

rmdir

Correct Answer : rmdir

97 .

Which symbol will be used with grep command to match the pattern pat at the end of a line?

A)

pat$

B)

$pat

C)

pat^

D)

^pat

Correct Answer : pat$

98 .

Which command is used to display all the lines with the string 'sales' from the file empl.lst?

A)

/sales > empl.lst

B)

cut sales empl.lst

C)

grep sales empl.lst

D)

cat | /sales > empl.lst

Correct Answer : grep sales empl.lst

99 .

Which of the following commands is not the vi Input mode command?

A)

R

B)

j

C)

S

D)

rch

Correct Answer : j

100 .

In vi editor, forward search is performed using the command.

A)

/pat

B)

:pat

C)

?pat

D)

All of the above

Correct Answer : /pat

101 .

Which of the following special shell variables is used to process number of the last background job?

A)

$*

B)

$#

C)

$0

D)

$!

Correct Answer : $!

102 .

Which option will be used with ps command to show the entire command line of the process being run?

A)

-f

B)

-1

C)

-2

D)

-4

Correct Answer : -f

103 .

Which of the following command addresses all users who are currently hooked on?

A)

mail

B)

mesg

C)

wall

D)

write

Correct Answer : wall

104 .

Which shell's wild-cards is used to match a single character?

A)

*

B)

?

C)

[ijk]

D)

[!ijk]

Correct Answer : ?

105 .

Which command is used to copy the three files wb, collect and mon into the misc directory, under the same, when you were currently in the programs directory?

A)

tar wb collect mon /misc

B)

cp wb collect mon ../misc

C)

copy wb collect mon /misc

D)

copy wb ../misc collect ../misc mon ../misc

Correct Answer : cp wb collect mon ../misc

106 .

The commonly used UNIX commands like date, ls, cat, etc. are stored in

A)

/dev directory

B)

/tmp directory

C)

/unix directory

D)

/bin and /usr/bin directories

Correct Answer : /bin and /usr/bin directories

107 .

Which of the following commands is used to remove files with confirmation prompt from the user file system which have neither been accessed nor modified i the last one year?

A)

find -mtime +365 | rm

B)

find -name - mtime + 365 / - ok rm

C)

grep (/usr/*) - mtime + 365 | -ok rm

D)

find /user/* $-mtime + 365 - a - atime +365 $ - OK rm {} \;

Correct Answer : find /user/* $-mtime + 365 - a - atime +365 $ - OK rm {} \;

108 .

Which of the following commands is used to summarize the disk usage?

A)

du

B)

disk

C)

fdisk

D)

chkdsk

Correct Answer : du

109 .

Which command is used to sort the lines of data in a file in alphabetical order?

A)

st

B)

sh

C)

sort

D)

sort -r

Correct Answer : sort

110 .

If a file has read and write permissions for the owner, then the octal representation of the permissions will be

A)

1

B)

3

C)

5

D)

6

Correct Answer : 6

111 .

Which of the following files are known as special files in Unix?

A)

/dev/tty

B)

/dev/null

C)

sample.txt

D)

/dev/null and /dev/tty

Correct Answer : /dev/null and /dev/tty

Explanation : There are two special files named /dev/null and /dev/tty which is used in UNIX for special purposes. For example, if we want to check whether the program runs successfully without seeing its output on the screen or may not want to save output in a file either. For this purpose, a special file /dev/null is used. It accepts any stream without growing in size. The second file /dev/tty is the one used for indicating one’s terminal.

112 .

What is the output of the following Unix command?

$ wc  -c  *.câ€‹

A)

erroneous

B)

undefined

C)

total size of .c files

D)

size of each .c file

Correct Answer : total size of .c files

Explaination : We can make the command ignorant of its source using the pipeline. Above command is also an example of the same. It will simply display the total size of those files having a .c extension in the current directory.

113 .

In Unix, for what purpose bc command is used?

A)

as an editor

B)

as a calculator

C)

for copying files

D)

as a process table viewer

Correct Answer : as a calculator

Explanation : bc command is used for invoking calculator on UNIX system. It comes with a wide library for performing calculations. The power of this tool can be derived from the fact, that it can perform calculations up to and above 900 digits!

114 .

Which process is immediately set up by the kernel when we log on to a Unix system?

A)

shell

B)

bash

C)

parent

D)

System

Correct Answer : shell

Explanation : As we log on to a UNIX system, a process is immediately set up by the kernel. This process represents a UNIX command which may sh (Bourne shell), ksh (Korn shell), csh (C shell) or bash (Bash). This process remains alive until we log out when it is killed by the kernel.

115 .

Which command shows some attributes of a process?

A)

ps

B)

$$

C)

pid

D)

HOME

Correct Answer : ps

Explanation : ps command is used to show some attributes of a process. This command reads through the kernel’s data structures and process tables to fetch the characteristics of a process. By default, ps command displays the processes owned by the user running the command.

116 .

Which of the following system call is used for creating a new process in Unix?

A)

read

B)

wait

C)

fork

D)

new

Correct Answer : fork

Explanation : A process in UNIX is created using fork() system call. It creates an exact copy of the process that invokes it. Now there will be two processes, one parent process and one child process. The process which invokes the fork system call is called parent process and the new process created is called child process.

117 .

You can append to a file instead of overwriting by using the

A)

< symbols

B)

> symbols

C)

<< symbols

D)

>> symbols

Correct Answer : >> symbols

118 .

The [line number G] key allows you

A)

to move cursor down by one line

B)

to move cursor left by one position

C)

to move cursor right by one position

D)

to move cursor to the beginning of the line specified by the number

Correct Answer : to move cursor to the beginning of the line specified by the number

119 .

Which of the following commands is used to have a two-way communication with any person who is currently logged in?

A)

grep

B)

write

C)

mail

D)

mesg

Correct Answer : write

120 .

Which command is used with vi editor to move the cursor to the left?

A)

h

B)

i

C)

j

D)

k

Correct Answer : h

121 .

The special shell variable $* is used

A)

to process number of the current shell

B)

to list the positional parameters

C)

to name the command being executed

D)

to exit status of ast command executed.

Correct Answer : to list the positional parameters

122 .

The cat command is used to

A)

print a file

B)

copy a file

C)

display a file

D)

capture a file

Correct Answer : display a file

123 .

The UNIX file system stores a data in physical blocks of

A)

256 bytes

B)

512 bytes

C)

1024 bytes

D)

2048 bytes

Correct Answer : 512 bytes

124 .

Which command is used to terminate all processes in your own system except the login shell?

A)

kill 0

B)

kill 1

C)

cancel 1

D)

cancel all

Correct Answer : kill 0

125 .

Which operator will be used with chmod command to assign absolute permission?

A)

-

B)

+

C)

%

D)

=

Correct Answer : =

126 .

Which of the following signs is used to back up over typing errors in vi?

A)

!

B)

@

C)

$

D)

#

Correct Answer : #

127 .

Major expressions used with find command to select file is it has been accessed in more than 375 days, is

A)

-atime -365

B)

-mtime -365

C)

-atime +365

D)

-mtime + 365

Correct Answer : -atime +365

128 .

Which of are following internal commands is used in mail to forward mail to user in user-list?

A)

m user-list

B)

e user-list

C)

r user-list

D)

d user-list

Correct Answer : m user-list

129 .

Which of the following directories contain all the Alias created by a user, including his login directory?

A)

/etc

B)

/usr

C)

/dev

D)

/tmp

Correct Answer : /usr

130 .

Which of the following commands is used to obtain a list of all files by modification time?

A)

ls -1

B)

ls -t

C)

ls -i

D)

ls -R

Correct Answer : ls -t

131 .

The % key allows you

A)

to move the cursor backward to the beginning of a word

B)

to move the cursor to the upperleft corner of the screen

C)

to move the cursor to the first column in the current line

D)

to move the cursor to a matching delimiter, when a delimiters a parenthesis, a bracket, or a brace.

Correct Answer : to move the cursor to a matching delimiter, when a delimiters a parenthesis, a bracket, or a brace.

132 .

The field separator in cut command is specified with

A)

-a option

B)

-d option

C)

-r option

D)

-x option

Correct Answer : -d option

133 .

Which of the following options will be used to display number of blocks used by a file?

A)

-c

B)

-d

C)

-s

D)

-i

Correct Answer : -s

134 .

Which command is used to make all files and sub-directories in the directory (progs) executable by all users?

A)

chmod -R a+x progs

B)

chmod -1 a+x progs

C)

chmod -x a+x progs

D)

chmod -R 222 progs

Correct Answer : chmod -R a+x progs

135 .

Which command is used to copy a file wb with the same name from the programs directory to the misc directory?

A)

tar programs/wb misc/wb

B)

copy programs/wb misc/wb

C)

cp programs/wb misc

D)

copy a:programs/wb b:misc/wb

Correct Answer : cp programs/wb misc

136 .

Which is the earliest and most widely used shell that came with the UNIX system?

A)

C shell

B)

Korn shell

C)

Smith shell

D)

Bourne shell

Correct Answer : Bourne shell

137 .

The seventh field of /etc/password is

A)

login

B)

shell

C)

home

D)

password

Correct Answer : shell

138 .

Which command is used to display the end of the file?

A)

tail

B)

eof

C)

bof

D)

head - r

Correct Answer : tail

139 .

Which command is used to display the device name of the terminal you are using?

A)

ls

B)

stty

C)

tty

D)

who

Correct Answer : tty

140 .

The ls -l command tells

A)

who the owner of the file is

B)

the name of the group owner of the file

C)

how large the file is and when the file was last modified.

D)

All of the above

Correct Answer : All of the above

141 .

Which command is used to set the three permissions for all the three categories of users of a file?

A)

chmod

B)

chgrp

C)

chusr

D)

chown

Correct Answer : chmod

142 .

Which of the following commands can be used to get information about all users who are currently logged into the system?

A)

1 /u

B)

who

C)

which

D)

who am i

Correct Answer : who

143 .

Which command is used to locate all the .profile files in the system?

A)

ls profile

B)

l -u .profile

C)

cd /.profile

D)

find /-name profile -print

Correct Answer : find /-name profile -print

144 .

Which Unix command is used for locating files?

A)

loc

B)

find

C)

type

D)

search

Correct Answer : find

Explanation : find is one of the most powerful tools of the UNIX system. It recursively examines a directory tree to look for file matching based on some criteria and then takes some action on the selected files.

145 .

Which command is used for preparing a file for printing?

A)

pr

B)

cd

C)

cat

D)

print

Correct Answer : pr

Explanation : The pr command is used for preparing a file by adding suitable headers, footers and formatted text. This command is used with a filename as an argument. For example,

$ pr  dept.lst
May  06  10:38  1998  dept.lst  Page 1
01:accounts:6213
02:admin:5423
03:marketing:6521
04:personnel:2365
 
.....blank lines.......â€‹

146 .

Which command is used for sorting a file on specified fields?

A)

pr

B)

cut

C)

sort

D)

tail

Correct Answer : sort

Explanation : Sorting is the ordering of data in ascending or descending order. The sort command is used for ordering a file. Like cut command, sort also identifies fields and perform sorting on specified fields. To sort any file, just provide the name of the file as an argument with sort command.

$ sort emp.lstâ€‹

147 .

Which Unix command is used for locating repeated and non-repeated lines?

A)

cut

B)

sort

C)

uniq

D)

paste

Correct Answer : uniq

Explanation : When we concatenate or merge files, we can encounter the problem of duplicate entries creeping in. UNIX offers a special command (uniq) which can be used to handle these duplicate entries. We can also use the sort -u command for doing the same piece of work.

148 .

Which command is used for translating characters?

A)

tr

B)

sort

C)

trans

D)

paste

Correct Answer : tr

Explanation : The translate (tr) filter is used for manipulating individual characters in a line. Usually, tr command translates characters using one or two compact expressions. The syntax for using tr command is,

$ tr  options  expression1  expression2  standard inputâ€‹

149 .

Which of the following command will be used for searching "director" in emp.lst?

A)

grep â€œdirectorâ€

B)

grep -director emp.lst

C)

grep -v â€œdirectorâ€ emp.lst

D)

grep â€œdirectorâ€ emp.lst

Correct Answer : grep â€œdirectorâ€ emp.lst

Explanation : Because grep command is also a filter, it can search it’s standard input for the pattern. For example, the command grep “director” emp.lst will search the file emp.lst for the pattern “director” and will display the lines containing this pattern.

150 .

Which of the following commands is known as stream editor?

A)

td

B)

sed

C)

grep

D)

None of the above

Correct Answer : sed

Explanation : sed is a multipurpose tool which performs the function of several filters together. This filter is derived from the ed (original UNIX editor). It performs non-interactive operations on a data stream. It uses instructions to act on a text for selecting lines, with an action to be taken.

151 .

What is a shell script?

A)

group of functions

B)

group of commands

C)

a file containing special symbols

D)

a file containing a series of commands

Correct Answer : a file containing a series of commands

Explanation : When we have to execute a series of commands altogether, we store them in a file which is itself executed as a shell script. A shell script is basically a computer program designed to be run by the UNIX shell.

152 .

The second set of the three permissions (r-) indicates that

A)