Shell Questions | PrepOps.Dev

#1

What does this line in shell scripts means?: #!/bin/bash

#2

True or False? When a certain command/line fails in a shell script, the shell script, by default, will exit and stop running

#3

What do you tend to include in every script you write?

#4

Today we have tools and technologies like Ansible, Puppet, Chef, ... Why would someone still use shell scripting?

#5

How to define a variable with the value "Hello World"?

#6

How to define a variable with the value of the current date?

#7

How to print the first argument passed to a script?

#8

Write a script to print "yay" unless an argument was passed and then print that argument

#9

What would be the output of the following script?

#!/usr/bin/env bash
NINJA_TURTLE=Donatello
function the_best_ninja_turtle {
        local NINJA_TURTLE=Michelangelo
        echo $NINJA_TURTLE
}
NINJA_TURTLE=Raphael
the_best_ninja_turtle

#10

Explain what would be the result of each command:

echo $0
- echo $?
- echo $$
- echo $#

#11

What is $@?

#12

What is difference between $@ and $*?

#13

How do you get input from the user in shell scripts?

#14

How to compare variables length?

#15

Explain conditionals and demonstrate how to use them

#16

In shell scripting, how to negate a conditional?

#17

In shell scripting, how to check if a given argument is a number?

#18

How to perform arithmetic operations on numbers?

#19

How to perform arithmetic operations on numbers?

#20

How to check if a given number has 4 as a factor?

#21

What is a loop? What types of loops are you familiar with?

#22

Demonstrate how to use loops

#23

How do you debug shell scripts?

#24

Running the following bash script, we don't get 2 as a result, why?

x = 2
echo $x

#25

How to extract everything after the last dot in a string?

#26

How to extract everything before the last dot in a string?

#27

Generate 8 digit random number

#28

Can you give an example to some Bash best practices?

#29

What is the ternary operator? How do you use it in bash?

#30

What does the following code do and when would you use it?

diff

#31

What are you using for testing shell scripts?

#32

Argument Check

Objectives

Note: assume the script is executed with an argument

Write a script that will check if a given argument is the string "pizza"
If it's the string "pizza" print "with pineapple?"
If it's not the string "pizza" print "I want pizza!"

#33

Basic Date

Objectives

Write a script that will put the current date in a file called "the_date.txt"

#34

Count Chars

Objectives

Read input from the user until you get empty string
For each of the lines you read, count the number of characters and print it

Constraints

You must use a while loop
Assume at least three lines of input

#35

Directories Comparison

Objectives

You are given two directories as arguments and the output should be any difference between the two directories

#36

Empty Files

Objectives

Write a script to remove all the empty files in a given directory (including nested directories)

#37

Shell Scripting - Factors

Objectives

Write a script that when given a number, will:

Check if the number has 2 as factor, if yes it will print "one factor"
Check if the number has 3 as factor, if yes it will print "one factor...actually two!"
If none of them (2 and 3) is a factor, print the number itself

#38

Files Size

Objectives

Print the name and size of every file and directory in current path

Note: use at least one for loop!

#39

Great Day

Objectives

Write a script that will print "Today is a great day!" unless it's given a day name and then it should print "Today is "

Note: no need to check whether the given argument is actually a valid day

#40

Shell Scripting - Hello World

Objectives

Define a variable with the string 'Hello World'
Print the value of the variable you've defined and redirect the output to the file "amazing_output.txt"

#41

It's Alive!

Objectives

Write a script to determine whether a given host is down or up

#42

Number of Arguments

Objectives

Write a script that will print "Got it: " in case of one argument
In case no arguments were provided, it will print "Usage: ./ "
In case of more than one argument, print "hey hey...too many!"

#43

Sum

Objectives

Write a script that gets two numbers and prints their sum
Make sure the input is valid (= you got two numbers from the user)
Test the script by running and passing it two numbers as arguments

Constraints

Use functions