Unix System : Practice Questions and Answers

Browse topic-based Unix System practice sets.

73 practice sets · Page 4 of 4

Unix SystemMediumBasics

61.

Which statement is not true about process 0 in the Unix operating system?

Process 0 is not created by fork system call

Process 0 is a special process created when system boots

Process 0 is called init process

After forking process 1, process O becomes swapper process

View Answer

Correct Answer: C — Process 0 is called init process

Explanation:

Process 0 is typically the sched or swapper process, while Process 1 is the init process. Therefore, stating that Process 0 is the init process is incorrect.

Unix SystemHardBasics

62.

Which of the following commands would return the process_id of the sleep command?

sleep 1 & echo $!

sleep 1 & echo $*

sleep 1 & echo $?

sleep 1 & echo $$

View Answer

Correct Answer: A — sleep 1 & echo $!

Explanation:

The special variable $! holds the process ID of the most recently executed background pipeline, which would be the sleep command in this case.

Unix SystemMediumBasics

63.

What does the following command do?

grep -vn "abc" x

It will print the specific line numbers of file x in which there is a match for the string "abc"

It will print total no of the lines in file x that match the search string "abc"

It will print all of the lines in the file x that match the search string "abc"

It will print all of the lines in file x that do not match the search string "abc", along with their line numbers

View Answer

Correct Answer: D — It will print all of the lines in file x that do not match the search string "abc", along with their line numbers

Explanation:

The grep command with -v inverts the search to output lines that do not match the pattern, while -n includes the line numbers.

Unix SystemEasyBasics

64.

The Unix Kernel maintains two key data structures related to processes, the progress table and the user structure. Which of the following information is not a part of the user structure?

System call state

File descriptor table

Scheduling parameters

Kernel stack

View Answer

Correct Answer: C — Scheduling parameters

Explanation:

Scheduling parameters (like priority and recent CPU usage) are kept in the process table (proc structure) because they must be accessible even when the process is swapped out, unlike the user structure.

Unix SystemMediumBasics

65.

A Unix file may be of the type:

Regular file

Directory file

Device file

All of the above

View Answer

Correct Answer: D — All of the above

Explanation:

UNIX supports multiple file types, primarily regular files, directories, and special (device) files, adhering to its "everything is a file" philosophy.

Unix SystemMediumBasics

66.

Match the following for Unix system calls:

List – I	List – II
(a) exec()	(i) Creates a new process
(b) brk()	(ii) Replaces the core image of a process
(c) wait()	(iii) Changes data segment size
(d) fork()	(iv) Blocks caller until child terminates

(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)

(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)

View Answer

Correct Answer: D — (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)

Explanation:

UNIX system calls provide direct interfaces to the kernel: exec() replaces the process image, brk() changes the data segment space allocation, wait() pauses execution until a child finishes, and fork() spawns a new process.

Unix SystemMediumBasics

67.

WOW32 is a:

Kernel - mode objects accessible through Win 32 API

Win 32 API library for creating processes and threads

Special execution environment used to run 16 bit Windows applications on 32 - bit machines

Special kind of file system to the NT name space

View Answer

Correct Answer: C — Special execution environment used to run 16 bit Windows applications on 32 - bit machines

Explanation:

WOW32 (Windows on Windows 32-bit) is a subsystem that allows older 16-bit Windows applications to run seamlessly on 32-bit Windows operating systems.

Unix SystemHardBasics

68.

The Unix command:

$ vi file1 file2

Edits file1 and stores the contents of file1 in file2

Both files i.e. file1 and file2 can be edited using 'ex' command to travel between the files

Both files can be edited using 'mv' command to move between the files

Edits file1 first, saves it and then edits file2

View Answer

Correct Answer: B — Both files i.e. file1 and file2 can be edited using 'ex' command to travel between the files

Explanation:

When multiple files are opened in vi, they are loaded into the buffer array, and 'ex' commands like :n (next) can be used to switch between them.

Unix SystemEasyBasics

69.

______ maintains the list of free disk blocks in the Unix file system.

I-node

Super block

File allocation table

Boot block

View Answer

Correct Answer: B — Super block

Explanation:

The Super block contains critical metadata about the file system, including the size, status, and a list of free disk blocks.

Unix SystemHardBasics

70.

A part of Windows 2000 operating system that is not portable is

Device Management

Virtual Memory Management

Processor Management

User Interface

View Answer

Correct Answer: B — Virtual Memory Management

Explanation:

Virtual Memory Management is heavily dependent on specific hardware architectures and memory management units, making it less portable across different platforms.

Unix SystemEasyBasics

71.

Match the following with reference to Unix shell scripts:

List-I	List-II
(a) $?	(i) Process ID of current shell
(b) $#	(ii) All arguments as a single string
(c) $$	(iii) Number of command line arguments
(d) $*	(iv) Exit status of last command

(a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)

(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)

(a)-(i), (b)-(iii), (c)-(i), (d)-(iv)

View Answer

Correct Answer: B — (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

Explanation:

Specific shell variables map to strict definitions: $? gives the last exit status, $# gives the argument count, $$ is the current process ID, and $* returns all arguments.

Unix SystemMediumBasics

72.

The output generated by the LINUX command:

$ seq 1 2 10

will be

1 3 5 7 9

1 2 10

1 5 10

1 2 3 4 5 6 7 8 9 10

View Answer

Correct Answer: A — 1 3 5 7 9

Explanation:

The seq 1 2 10 command generates a sequence starting at 1, incrementing by 2, and ending before it exceeds 10, outputting 1, 3, 5, 7, 9.

Unix SystemHardBasics

73.

In UNIX, ______________ creates three subdirectories: 'PIS' and two subdirectories 'progs' and data from just created subdirectory 'PIS'.

mkdir PIS/progs data

mkdir PIS progs data

mkdir PIS PIS/progs PIS/data

mkdir PIS/progs PIS/data PIS

View Answer

Correct Answer: C — mkdir PIS PIS/progs PIS/data

Explanation:

The command mkdir PIS PIS/progs PIS/data explicitly creates the parent directory 'PIS' along with its subdirectories 'progs' and 'data' in one go.

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List – I

List – II

(a) exec()

(i) Creates a new process

(b) brk()

(ii) Replaces the core image of a process

(iii) Changes data segment size

(d) fork()

(iv) Blocks caller until child terminates

List-I

List-II

(a) $?

(i) Process ID of current shell

(b) $#

(ii) All arguments as a single string

(iii) Number of command line arguments

(d) $*

(iv) Exit status of last command