Computer Science - UNIX – Multiple Choice Question

Question 1 of 200

1. Question

UNIX was developed by

Bell Lavs
Berkley Software Group
California University
American Defence Academy

Question 2 of 200

2. Question

Chocolate Chip is

a latest Intel product
another name for BSD 4.2 Version
another name for System V
another name for System III

Question 3 of 200

3. Question

Which of the following features of UNIX may be used for inter process communication?

signals
pipes
samaphore
Message Queues

Question 4 of 200

4. Question

Pick the incorrect statements

Shell is a command interpreter
Shell is the interface between user and kernel.
System can't work without a shell.
Shell is a program.

Question 5 of 200

5. Question

UNIX is

a multi-user system
a real-time system
a multi-task system
name of a file in the root directory

Question 6 of 200

6. Question

Which of the following statements best explains a process?

It is a program
It is a program in execution.
It is an instance of a program in execution.
It is a program that uses system calls.

Question 7 of 200

7. Question

In a system, if 5 people are currently using the vi editor, then the number of corresponding processes will be

1
5
2
0

Question 8 of 200

8. Question

Kernel is not involved

When a read operation is done
When a pressed key is echoed on to the screen
in resource allocation
none of the above

Question 9 of 200

9. Question

The command
echo welcome > /dev/tty

echoes welcome in all the terminals that are switched on.
echoes welcome in all the terminals that are logged on.
echoes welcome only in the terminal in which it is run.
signals the error message - Terminal number not specified.

Question 10 of 200

10. Question

/dev/null

is a file
has write permission for all
is the UNIX built-in dustbin
none of the above

Question 11 of 200

11. Question

The advantage of binary files over text files is that

it is compact
it can be accessed faster
many commands (like cat) assume the named file to be a binary file
they are more reliable

Question 12 of 200

12. Question

The permission bits of a file noname, can be set to _rws_ _x_ _x by the command

chmod 711 noname
chmod go-rw noname
chmod 2711 noname
none of the above

Question 13 of 200

13. Question

/bin/passwd has the user execution permission set to ‘s’ because

it is not executable
it should allow users who don't have write permission to /etc/passwd to write to it
/etc/passwd is write protected
this facility assigns to the users, permissions of the program owner, temporarily.

Question 14 of 200

14. Question

If one doesn’t want anyone else to read or write to a file named datfile, except through a program in file filex, then he may use

chmod u+s filex ; chmod go-rw datfile
chmod u+s datfile ; chmod go-rw filex
chmod 4711 datfile ; chmod go-rw filex
chmod 4711 filex ; chmod go-rw datfile

Question 15 of 200

15. Question

Writing a C program that accepts input from keyboard, rather than from a file is advantage geous because

keyboard is a file that is already open
it facilitates batch processing
it can be used in a pipe, if it writes to stdout
none of the above

Question 16 of 200

16. Question

Consider the following command that invokes the executable file a.out, with the following command line arguments a.out God loves you
argv[1][2] corresponds to the character

e
o
.
d

Question 17 of 200

17. Question

In the previous question after the operation argv++, the value of argv[1][2] will be

e
d
v
undefined

Question 18 of 200

18. Question

Which of the following string functions can be used to find the last occurrence of a given character in a given string?

strncmp
strncpy
strchr
none of the above

Question 19 of 200

19. Question

Choose the correct statements.

The function stat refers a file by its name.
The function stat refers a file by its file descriptor.
The function fstat refers a file by its file descriptor.
The function fstat refers a file by its name.

Question 20 of 200

20. Question

Which of the following fields in the structure stat, has information about the permission setting of a file?

st_gid
st_mode
st_ino
st_uid

Question 21 of 200

21. Question

To simulate the command “system”, which of the system calls – fork, wait, and excel is/are to be used ?

fork and wait
all three
fork and excel
wait and excel

Question 22 of 200

22. Question

Consider the program
main()
{
printf (“He arose a victor from\n”) ;
system (“date”) ;
printf(“the dark domain”) ;
}
if a.out is the executable code corresponding to the above source code, then the command a.out > outf

redirects the output of date to file out f
displays the output of date on the screen
prints everything on the screen
prints the two messages on the screen

Question 23 of 200

23. Question

The default permission bits of a file when it is created for the first time, is controlled by

chmod value
fmask value
umask value
none of the above

Question 24 of 200

24. Question

Let x.c be a C source code. The command cc ‘x.c > y

is equivalent to the command cc x.c ; mv a.out y
is equivalent to the command cc -o y x.c
serves no purpose
none of the above

Question 25 of 200

25. Question

Which of the following sections in the manual covers system calls?

1
2
3
4

Question 26 of 200

26. Question

Which of the following are not system calls ?

chmod
open
lseek
getc

Question 27 of 200

27. Question

Choose the correct statements.

C programs can directly make system calls.
System calls are functions used by the shell.
Library functions use system calls.
Library functions don't use system calls.

Question 28 of 200

28. Question

Which of the following remarks about system calls, library functions and UNIX commands are true?

System call is a part of kernel, while the other two are not a part of kernel
Unlike library functions, system calls and Unix commands are stand-alone programs
Library functions and UNIX commands use system calls
Unlike system calls, library functions and UNIX commands are stand-alone programs

Question 29 of 200

29. Question

The 2 in the manual entry access (2)

implies access is a system call
implies access is a library function
refers to the section number
none of the above

Question 30 of 200

30. Question

If path is set to . : /usr/x:/usr/bin, then

the command one type will be first checked in the current directory, the /usr/x and /usr/bin.
if a command is found in both /usr/x and /usr/bin, then the one in /usr/x will be executed.
in the previous choice, what happens is unpredictable.
if a command is found in both /usr/x and usr/bin, then the one in /usr/bin will be executed.

Question 31 of 200

31. Question

A file x is created with the following contents
echo today is :
date
If you type x, then

it echoes the message, followed by date.
it gives the desired output only if the execute permission of file x is set.
the desired output can be got by the command sh x, which works even if x has its execute permission not set.
none of the above

Question 32 of 200

32. Question

Shell script is preferable to other forms of programming because it

executes faster
enhances portability
occupies less space
makes programming task easier

Question 33 of 200

33. Question

Choose the incorrect statements.

Shell scripts can accept arguments
Shell scripts are interpreted
Shell is a programming language
Shell scripts are compiled

Question 34 of 200

34. Question

Files that store data in the same format as used in program are called

binary files
source file
text file
core

Question 35 of 200

35. Question

To allow only one user to work with a particular file at a particular time, one has to use

semaphore
critical region
locking
dedicated mode

Question 36 of 200

36. Question

Which of the following remarks about realloc are ture ?

It allocates memory of required size that need not be contiguous
It never shifts the existing the existing block
It can work only with an existing block of memory
It may shift the existing block

Question 37 of 200

37. Question

The differences between malloc() and calloc() are :

malloc is used for dynamic allocation of memory, while calloc can't be used for that purpose.
malloc needs only one argument, while calloc needs two.
unlike malloc, colloc allocates memory and initializes it to 0.
malloc needs two arguments and calloc only one.

Question 38 of 200

38. Question

The file that stores an integer as a sequence of characters is a

text file
data file
binary file
core

Question 39 of 200

39. Question

If cat x, prints garbage, then x is probably a

data file
binary file
text file
source file

Question 40 of 200

40. Question

Which of the following file names can be found in more than one directory?

passwd
bin
date
none of the above

Question 41 of 200

41. Question

/bin

is a bucket for storing information
has files in binary code
is a directory
none of the above

Question 42 of 200

42. Question

The main reasons for the success of pipes are

the availability of many filter programs
UNIX treats devices as files
it provides a 2-way communication channel
all of the above

Question 43 of 200

43. Question

Which of the following are not filter programs?

date
sort
cat
grep

Question 44 of 200

44. Question

Redirection in pipes can be achieved by using

>
>>
tee
lpr

Question 45 of 200

45. Question

Choose the correct statements.

The symbols > and | are both processed by shell
> can be used to direct output to a named file
| can be used to direct output to programs
Filter programs can be piped

Question 46 of 200

46. Question

The command who | sort – file1 – file2

results in an error
sorts the contents of file1 and puts it in file2
puts in file2, the sorted output of who, followed by sorted contents of file1
none of the above

Question 47 of 200

47. Question

If the command cat x, is executed after successfully executing the command time sort filename > x, then

only the time details will be displayed
only the sorted contents of the file filename will be displayed
an error message will be displayed
the sorted contents of the file filename, along with the time information will be displayed

Question 48 of 200

48. Question

Which of the following information is not present in an i-node?

Contents of the file
size of the file
Name of the file
Permission setting of the file

Question 49 of 200

49. Question

The system identifies a file by its

name
absolute path
file owner
inode number

Question 50 of 200

50. Question

The system identifies the end of a file by the

EOF character
file size
i-node number
none of the above

Question 51 of 200

51. Question

The command line argument a.out x ‘a b’ “c d”

is acceptable
is acceptable if the double quotes are replaced by single quotes
is acceptable if the single quotes are replaced by double quotes
none of the above

Question 52 of 200

52. Question

Which of the following metacharacters will be recognized by the shell, even if it comes within double quotes?

$
*
?
None of these

Question 53 of 200

53. Question

lint should be used

before compilation
after compilation
to analyze a C code
none of the above

Question 54 of 200

54. Question

Environment variables can be accessed by

system programs
C programs
shell scripts
none of the above

Question 55 of 200

55. Question

Which of the following are character special file?

Terminal
Printer
Modem
Tape Drive

Question 56 of 200

56. Question

If one exports a variable

variables placed in the environment by a child process are not inherited by the pare process.
it is passed to all its descendant processes
it dies when the shell that created it dies
only the first two choices are correct

Question 57 of 200

57. Question

Profiels are

tools that analyze the run time behavior of a program
tools that check a C code for cross file consistency
tools that keep track of evolving versions of a file
none of the above

Question 58 of 200

58. Question

The shell command

does nothing
can be used to cause infinite looping
can take arguments but it cannot act on them
can be used to indicate a comment

Question 59 of 200

59. Question

Which of the following tools can be used to keep track of evolving versions of a file?

make
yacc
sccs
dv

Question 60 of 200

60. Question

The . (dot) shell command

can take command line argument
will fork a child shell to execute the named shell script
can be used to change the environment of the current shell
all of the above

Question 61 of 200

61. Question

m4

is a macro processor
can be used to preprocess C code
can be used to Proprocess assembly language program
none of the above

Question 62 of 200

62. Question

The first thing that is searched when a command references a file is its

i-node
i-node number
permission setting
none of the above

Question 63 of 200

63. Question

cc command sequentially invokes

Preprocessor, compiler and link editor
compiler and link editor
preprocessor, compiler, assembler and link editor
compiler, assembler and like editor

Question 64 of 200

64. Question

Among the directory entries, i-node and the file contents, which will be changed when a file is updated?

Only directory entry and file contents
Only i-ode and file contents
All the three
None of the above

Question 65 of 200

65. Question

The cc command

can take more then one argument
can act on files with. c or .o extension
creates . o files by default when more than one argument with. c extension is present
if provided with more than one argument, immediately terminates if the first argument fails to compile successfully

Question 66 of 200

66. Question

The mv command changes

only the directory entry
only the directory entry and i-node
only the i-node number
none of the above

Question 67 of 200

67. Question

If 7 terminals are currently logged on, then the command
date ; who | wc -1, displays

date followed by 7
date followed by 8
date followed by 1
an error message

Question 68 of 200

68. Question

Choose the correct answers if the command Is -1 /dev/mt 0 displays
brw_rw_ _ _ _ 1 root 3, 0 jan 18 11:05 mt0

The 'b' indicates that it is a special file
mt 0 indicates that it is a tape drive
mt 0 indicates that it is a mounted tape
The 'b' indicates that data transfer is done in blocks

Question 69 of 200

69. Question

Choose the correct statements.

1d x.o is a valid command (assume x.o exists)
1d x.o is same as cc x.o
cc x.s is a valid command (assume x.s exists)
All of the above

Question 70 of 200

70. Question

cat /dev/tty

throws garbage onto the terminal tty
just echoes what you type, line by line
terminates if one types control d, at the beginning of a line
terminates if one types control d, anywhere in a line

Question 71 of 200

71. Question

The header files used in C programs are usually found in

/bin/include
/usr/bin/include
/dev/include
/usr/include

Question 72 of 200

72. Question

The command pwd displays /x/y. After executing the command chmod u-x, which of the following commands will not work?

cd . .
1s
chmod u+x
pwd

Question 73 of 200

73. Question

A C program should be compiled with -g option (like cc -g x. c) to use

prof
make
1prof
sdb

Question 74 of 200

74. Question

The difference between a pipe and a regular file is that

unlike a regular file, pipe is not a file.
the data in a pipe is transient, unlike the contents of a regular file.
pipes forbid random accessing, while regular files do allow this.
all of the above

Question 75 of 200

75. Question

Choose the correct statements.

The default linking arrangement for cc is dynamic.
Dynamically linked programs save disk storage.
Dynamically linked programs enhances shareability of library routines.
Dynamically linked programs can be fixed or enhanced without relinking the applications that depend on it.

Question 76 of 200

76. Question

Context switch changes the process mode from

user to kernel mode
Kernel to user mode
kernel mode to the kernel process
kernel process to the kernel mode of some process

Question 77 of 200

77. Question

File x.c has 5 lines of code. The command
date | tee abc | sort – x,c | wc -1, displays

5
6
0
an error message

Question 78 of 200

78. Question

Which of the following comments about the signals system call are true?

It takes up two arguments
The second argument, is a function call
The second argument is a pointer to a function
The first argument is an integer

Question 79 of 200

79. Question

lint can analyze the named source code for

inconsistent usage
non portabilty
suspicious constructs
none of the above

Question 80 of 200

80. Question

Which of the following characteristics of the original process are preserved when, the exec system call is executed?

The current working directory
The open files
PID
PPID

Question 81 of 200

81. Question

Which of the following remarks about lex are true?

It generates a C program.
It produces a C code that consumes more memory than a C program that can be written separately to accomplish the same task.
It produces a C code that executes slower than a C program that can be written separately to accomplish the same task;
None of the above

Question 82 of 200

82. Question

Which of the following programs are not interactive?

passwd
date
grep
sh

Question 83 of 200

83. Question

lex can be used for

text processing
code enciphering
compiler construction
collecting statistical data of different patterns

Question 84 of 200

84. Question

The number of errors in the following shell script
echo How are you ?
read $answer
is

0
1
2
3

Question 85 of 200

85. Question

The read in the previous question is a

library function
system cali
shell command
none of the above

Question 86 of 200

86. Question

If lex.1 is a lex code then

the command lex lex.1 invokes lex to act on lex.1
the command lex lex.1 writes its output to the field lex.yy.c
lex.yy.c has the definition of the function yylex
lex library can be invoked by the compiler option 11

Question 87 of 200

87. Question

Choose the correct statements.

Any process has an associated owner ID and group ID.
Effective ID defines who you are for the duration of a process.
Real ID defines who you are for the duration of a process.
Effective ID is available in /etc/passwd file.

Question 88 of 200

88. Question

A file hai has the following shell script in it
echo Oh! what a wonderful day
echo Day I will never forget 1>&2
echo Day I will never ever get
The command sh hai > mn

puts all the three messages in mn
puts the second message both in mn and the screen
puts only the first and the third message in mn
results in an error

Question 89 of 200

89. Question

No shell script can take input from

stdin
the output of the previously executed command redirected to it
the file that holds the script
none of the above

Question 90 of 200

90. Question

The command cc x.c && a.out

is equivalent to cc x,c ; a.out
means execute a.out only when x.c compiles successfully
means execute a.out only if cc x,c returns a value 0 to the system
all of the above

Question 91 of 200

91. Question

Which of the following shell script’s looping features does not recognize the break command?

while
until
for
None of the above

Question 92 of 200

92. Question

Shell script

needs no compilation
is ideal for manipulating a file, character by character
is not good in arithmetic operations
enhances portability

Question 93 of 200

93. Question

The desirable features of a new shell script you write is that

it should take its input from stdin
on successful termination, it should exit with a non-zero value
it should not accept command line arguments
it does some cleaning up operation, on termination

Question 94 of 200

94. Question

Which of the following shell commands displays the contents of each of the command line arguments, one by one?

cat $*
cat '$*'
cat "$@"
cat "$*"

Question 95 of 200

95. Question

The disadvantage of a pipe is that

it is a one way communication channel
it dies along with the process that created it
it can't be shared by unrelated processes
none of the above

Question 96 of 200

96. Question

The state of signals are

preserved across a fork call
not preserved across a fork call
not preserved across an exec call
preserved across an exec call

Question 97 of 200

97. Question

A fork system call will fail, if

The previously executed statement is also a fork call.
the limit on the maximum number of processes in the system would be exceeded.
the limit on the maximum number of processes that can be under execution by a single user would be exceeded.
all of the above

Question 98 of 200

98. Question

Which of the following options for the shell command test should be followed by the file descriptor?

r
d
t
s

Question 99 of 200

99. Question

Which of the following displays the exit status of the last executed command?

echo $#
echo $$
echo $?
echo $!

Question 100 of 200

100. Question

Which of the following initiates the sequence of events that ultimately allows a user to login?

clri
sync
login
init

Question 101 of 200

101. Question

Which of the following file names cannot be displayed if 1s * is run?

-Xy
?X
.X
hidden

Question 102 of 200

102. Question

getc (stdin)

results in run time error
results in syntax error
is equivalent to getchar() ;
none of the above

Question 103 of 200

103. Question

Which of the following is not the work of a C-preprocessor?

Macro expansion
File inclusion
Conditional compilation
None of the above

Question 104 of 200

104. Question

Which of the following is used to write disk block images from memory to disk?

clri
sync
mkfs
stty

Question 105 of 200

105. Question

Choose the correct statement.

To read successive characters from an open file, getchar and scanf can be used interchangeably.
to read successive characters from an open file, getchar and read can be used interchangeably.
The read system call reads from the buffer.
None of the above

Question 106 of 200

106. Question

The following program
main ()
{
close (1) ;
print ( “HOw R U?” ) ;
}

is syntactically incorrect
results in a run-time error
will wait indefinitely, if executed
none of the above

Question 107 of 200

107. Question

The PID of the kernel process is

undefined
0
1
3

Question 108 of 200

108. Question

Choose the correct remarks.

exit and return can be used interchangeably
Use of return terminates the program
Use of exit terminates the program
exit returns a value to the system

Question 109 of 200

109. Question

Which of the following is an index to the array of open files maintained by the kernel for a user?

i-node
i-node number
File descriptor
File poiner

Question 110 of 200

110. Question

In which of the following directories does init reside?

root
bin
etc
usr

Question 111 of 200

111. Question

The command cat > x

is invalid
creates a file x and displays an error message
creates a file x and waits for the user to give input from the keyboard
none of the above

Question 112 of 200

112. Question

Which of the following are defined in stdio.h?

EOF
NULL
BUFSIZE
None of the above

Question 113 of 200

113. Question

The login prompt can be changed by changing the contents of the file

inittab
init
passwd
gettydefs

Question 114 of 200

114. Question

When the read system call encounters EOF, it returns

Some positive integer
some negative integer
0
-1

Question 115 of 200

115. Question

Which of the following library functions do not return a pointer to the structure FILE?

fopen
fclose
freopen
fwrite

Question 116 of 200

116. Question

Which of the following processes are involved in the process of allowing a person to login?

init
getty
login
kernel

Question 117 of 200

117. Question

Which of the following system calls reads 8 bits from the standard input? (assume buff is a pointer to the buffer area)

read(0, buff, .8)
read(1, buff, 8)
read(0, buff, 1)
read(1, buff, 1)

Question 118 of 200

118. Question

Which of the following are implemented as macros (rather than functions)?

getchar
getc
fgetc
fputc

Question 119 of 200

119. Question

Choose the correct statements.

errno is an external variable available to any 'C' program
errno is set to a value when an error occurs
errno is cleared when a nonerroneous call is made
errno cannot be used to find the cause of an error

Question 120 of 200

120. Question

When the user responds to login prompt

getty forks login process
login process replaces getty process
a shell will be created
none of the above

Question 121 of 200

121. Question

The shell command cat x y ? x

doesn't work
replaces the contents of file x, by the contents of file y
does nothing, other than displaying an error message
none of the above

Question 122 of 200

122. Question

Which of the following return file descriptor?

close
fopen
open
creat

Question 123 of 200

123. Question

To simulate the who command, one has to access the file

/etc/passwd
/bin/.login
/etc/utmp
/usr/usr_dat

Question 124 of 200

124. Question

A file system in UNIX has the four sections – boot block, super block, I-list and data block that are arranged in the order.

boot block, supe block, I-list and data block
boot block, data block, super block and I-list
boot block, data block, I-list and super block
super block, boot block, data block and I-list

Question 125 of 200

125. Question

stderr, stdout, stdin have the file descriptors

0, 1, 2 respectively
0, 2, 1 respectively
1, 0, 2 respectively
2, 1, 0 respectively

Question 126 of 200

126. Question

Which of the following functions can be used to randomly access a file?

fgetc
getc
fseek
ftell

Question 127 of 200

127. Question

A manual entry of the form xyz (3S)

implies xyz is a system call
implies xyz is a library function
means xyz is a library function that is part of the standard i/o package
means xyz is a library function that is part of the standard math library

Question 128 of 200

128. Question

The reference time adopted by UNIX is

Jan 1, 1970
jan 1, 1980
jan 1, 1982
jan 1, 1972

Question 129 of 200

129. Question

perror () can be simulated by using

errno and sys_nerr
sys_errlist and sys_nerr
sys_errlist and errno
none of the above

Question 130 of 200

130. Question

A process that uses CPU, cannot continue to use it if

the CPU time slice expires
a higher priority process arrives
it has to wait for an event to happen
it executes an exit statement

Question 131 of 200

131. Question

The command cd . / . . / .

serves no purpose
is invalid
is equivalent to cd . .
none of the above

Question 132 of 200

132. Question

The UNIX tool awk

can do both numerical and string comparison
decides from the context whether the comparison is numerical or alphabetical
signals an error if an alphabet is compared with a number
all of the above

Question 133 of 200

133. Question

Which of the following strings will be matched by awk, if / (x +) * y ! $ / is the specifed pattern to be searched for ?

x +x +x +y ! $
x x x x y ! $
x x x xy !
none of the above

Question 134 of 200

134. Question

When awk encounters strings in arithmetic expression,

it treats them as having the value 0
it treats them as having the value 1
it displays an error message
it is assigned an arbitrary value

Question 135 of 200

135. Question

Which of the following comments about awk are ture?

It is a text processing language
Arrays can be indexed by string
It has features for redirecting its output
None of the above

Question 136 of 200

136. Question

Which of the following UNIX tools, receives input only from the standard input?

awk
grep
sed
tr

Question 137 of 200

137. Question

If x,c is a file, then ed x,c creates a copy of x.c in

/etc
/usr
/tmp
/usr/bin

Question 138 of 200

138. Question

The number of 3’s in the output of the following C program
main ()
{
printf( “1” ) ; fork () ;
printf ( “2” ) fork () ;
fork () ; printf ( “3” ) ;
}
is

1
8
4
2

Question 139 of 200

139. Question

Which of the following processes has the PID 1?

kernel
unix
init
shell

Question 140 of 200

140. Question

Which of the following remarks about fgrep are true?

It is faster then grep.
It is compact to use.
It does not recognize any meta-character.
It can simultaneously search for different patterns.

Question 141 of 200

141. Question

Which of the following results in an error?

expr 4+5
expr 9-3
expr 2*3
expr 7/5

Question 142 of 200

142. Question

Which of the following is not a command delimiter?

new line
;
&
,

Question 143 of 200

143. Question

A file abc has the following shell script in it.
cat $q > $1.$$
the command sh abc filel

results in an error
is equivalent to cp $1 $1.$$
copies the contents of filel to another file that has the PID of the executing shell as its extension
none of the above

Question 144 of 200

144. Question

*?* will be the output of

echo *?*
echo '*?*'
echo "*?*"
echo \*\?\*

Question 145 of 200

145. Question

Which of the following shell variables can be used to customize the editors (like ex, vi)?

PATH
IFS
HOME
EXINIT

Question 146 of 200

146. Question

echo $x will output

hai
garbage
an empty line
none of the above

Question 147 of 200

147. Question

If the command exit it run twice followed by running the command echo $x, the output will be

hai
garbage
an empty line
none of these

Question 148 of 200

148. Question

An orphan process

is a child process that was terminated before the parent process
is adopted by the login shell
is adopted by the process dispatcher
will be denoted by the process status 0

Question 149 of 200

149. Question

Which of the following calls never returns an error?

getpid
fork
ioctl
open

Question 150 of 200

150. Question

The following C program
main ()
{
fork() ; fork () ; print f (“yes”) ;
}
prints yes

only once
twice
4 times
8 times

Question 151 of 200

151. Question

When a process makes a system call, its mode changes from

user to kernel
kernel to user
restricted to unrestricted
unrestricted to restricted

Question 152 of 200

152. Question

Choose the correct statements.

When a process makes a system call, a context switch is initiated.
kernel is not involved in servicing a system call.
When a process making a system call has to wait for an event to occur, then a process switch to the kernel process is initiated
system calls cannot be serviced in kernel mode.

Question 153 of 200

153. Question

The command 1s > xy

displays an error message, if xy exists and is write protected
if followed by cat xy, lists xy also
redirects errors, if any, to xy
none of the above

Question 154 of 200

154. Question

Shell functions

are another name for shell procedures
execute faster than shell procedures
are executed by a new shell
are not executed by a new shell

Question 155 of 200

155. Question

The cc command makes a total of

1 pass
2 passes
4 passes
5 passes

Question 156 of 200

156. Question

Which of the following is not invoked when the cc command executes?

/lib/cpp
/lib/cl
/bin/as
/bin/1d

Question 157 of 200

157. Question

creat will fail, if

there are too many open files
the filename is a directory
the named file already exists with its write permission off
the parent directory of the named file is write protected

Question 158 of 200

158. Question

Which of the following arguments to the open system call, will be discarded, if the named file already exists?

O_TRUNC
O_APPEND
O_EXCL
O_CREAT

Question 159 of 200

159. Question

UNder which of the following circumstances rm /y/x, cannot remove x?

If x is write protected, but y is not write protected.
If x is not write protected, but y is write protected.
If y has its execution permission bit off.
All of the above

Question 160 of 200

160. Question

File pointer

is a long integer
is of pointer data type
represents the position of the read-write head from the beginning of the file.
none of the above

Question 161 of 200

161. Question

The C compiler can be modified to compile programs coded in other high level languages just by changing

/lib/ccom
/lib/c2
/lib/c1
/bin/as

Question 162 of 200

162. Question

When a file is aliased

a new directory entry is created
a new i-node is created
the i-node number is shared
none of the above

Question 163 of 200

163. Question

setting the execute bit on has no meaning, if the file is a

directory
shell script
C source code
symbol table

Question 164 of 200

164. Question

Which of the following sections of an executable binary file has all uninitialised data items?

bss
Data
Header
symbol table

Question 165 of 200