Exam

Question 1

True or False?

One of the tasks that an operating system must perform is to manage the resources.
Four resources that an operating system must manage are: the file system,
input/output, processes and memory.

Answer 1

True

Question 2

The “cd ~” and “cd” commands in Linux will make your home directory
your home directory.

Answer 2

False

Question 3

The “cat” command can NOT be used to create a file.

Answer 3

False
The “cat” command in Linux can be used to create a file. You can use the “cat > filename” command to create a new file and start entering text into it. The “>” symbol is used to redirect the output of the “cat” command to a file with the specified filename.

Question 4

In Linux the “..” directory refers to the parent of the current working
directory.

Answer 4

True

Question 5

The “root directory” in Linux is represented by “\”.

Answer 5

False
False. In Linux, the root directory is represented by the forward slash (“/”) symbol, not the backslash (“”) symbol. The forward slash is used as the directory separator in Linux and UNIX-based systems, while the backslash is used as the directory separator in Microsoft Windows operating systems.

Question 6

The “rm” command can NOT be used to delete directories.

Answer 6

False. The “rm” command in Linux can be used to delete directories. However, if you try to delete a directory using the “rm” command, you will get an error message stating that the directory is not empty. To remove a directory and its contents, you can use the “rm -r” command, which will recursively remove all files and subdirectories within the specified directory.

Question 7

The commands “less filename” and “cat filename|less” both accomplish
the same task.

Answer 7

True

Question 8

Bash has a construct similar to switch in java which is called case and
proper syntax dictates that you must close a case construct with “endcase”.

Answer 8

False. Bash does have a construct similar to a switch statement in Java, which is called the “case” statement. However, in Bash, you do not need to use “endcase” to close a “case” block. Instead, you can use the “esac” keyword to signify the end of a “case” block.

Question 9

In class we discussed redirection of output and redirection of input. We
use the symbols&raquo_space; and > for redirection of output and < for redirection
of input.

Answer 9

True

Question 10

nano, vi and sed are examples of editors found on most linux systems that
can be used to create and edit text files.

Answer 10

True

Question 11

There are two ways to execute a linux script file. One way is to make the file
executable using “chmod” and the second way is to use the “bash” command.

Answer 11

True

Question 12

. Regex can NOT be used with sed.

Answer 12

False. Regular expressions (regex) can be used with sed, which is a stream editor used for filtering and transforming text.

Question 13

egrep ‘.$’ science.txt |wc –l will count the number of lines that end with
with a period

Answer 13

True

Question 14

sed in an interactive editor

Answer 14

False. Sed is not an interactive editor, it is a stream editor used for filtering and transforming text.

Question 15

ps –l displays all the processes currently running on the system.

Answer 15

True

Question 16

Bash does not support floating point (decimal fraction) data types.

Answer 16

True

Question 17

. It is possible to have two files with the same absolute name on a disk.

Answer 17

False. It is not possible to have two files with the same absolute name on a disk.

Question 18

Regex’s is an abbreviation for Regular Examples

Answer 18

False. “Regex” is an abbreviation for “Regular Expressions.”

Regular expressions (regex) are a powerful tool used to match and manipulate text patterns.

Question 19

The command “chmod 511 filename” would make the file executable for the
owner

Answer 19

True

Question 20

To input a value into a bash program you use the command “input”.

Answer 20

False. the command to read input from the user is “read”.

Question 21

Before you use a variable in bash programming you must first declare the
variable type.

Answer 21

False. In Bash, you don’t need to declare the variable type before using a variable. Bash variables are dynamically typed, which means that the type of a variable is determined by the value assigned to it at runtime.

Question 22

Which of the following commands would you use to determine the number of words
in the file.
a) head b) tail c) wc d) uniq e) none of these

Answer 22

C)
The command you would use to determine the number of words in a file is wc.

.

Question 23

. The printenv command is used to show a list of:
a) script variables b) environment variables c) shell operators
d) prototypes for a script. e) none of these

Answer 23

B)
The printenv command is used to show a list of environment variables.

Question 24

Which of the following commands will show all the processes on atlas:
a) ps -l b) ps -ef c) ls -la d) ps -all e) none of these

Answer 24

B)

The ps -ef command will show all the processes on Atlas.

Question 25

Which command will create a global variable:
a) shell b) global c) export d) set e) none of these

Answer 25

C)
The export command is used to create a global variable in Bash.

Question 26

Which of the following commands would you use to display the contents of a shell
variable.
a) echo b) cat c) more d) print e) none of
thes

Answer 26

A)

The echo command is used to display the contents of a shell variable.

Question 27

. Assume the current working directory (cwd) is your home directory and there is a
sub-directory called dir_1 in your home directory and you wish to move to the dir_1
directory. Which one of the following commands is incorrect.
a) cd /dir_1 b) cd ./dir_1 c) cd dir_1
d) they are all correct e) they are all incorrect

Answer 27

A)
Option (a) cd /dir_1 is incorrect as it specifies an absolute path and tries to change the directory to a folder called dir_1 located in the root directory, not in your home directory.

THIS MAY NOT BE ACCURATE

Question 28

. Write a bash program segment that will read a name and grade from the
keyboard and the display the name and a message according to the
following. Your program should continue to execute until the user presses
CTRL/C. (4 points)
The name the grade message
Where message is: “Failed” if grade is less than 50
“Passed” if grade is between 50 and 100
“Invalid value” if grade is greater than 100

Answer 28

!/bin/bash

while true
do
read -p “Enter name: “ name
read -p “Enter grade: “ grade

if [[ $grade -lt 0 || $grade -gt 100 ]]; then
    echo "$name: Invalid value"
elif [[ $grade -lt 50 ]]; then
    echo "$name: Failed"
else
    echo "$name: Passed"
fi done