Question

Unix code problem 
Write a shell script that does the following :
Read many lines of text from the standard input device (keyboard) and copy 

them to the standard output. Precede each output line with a line number

Explain all steps

Answer 1

Let's break the problem into two steps:

1. Getting a multi-line input

Firstly, initialize the a variable called text to an empty string value (text = "")

Next, we read input to a variable c as "read c" for the current iteration of loop

Next, to get a multi line input, we use the while loop with the condition always set to true. This enables us to enter the string in multiple lines. Now, an infinite loop is a problem. We can choose out method of termination using the if statement:

if [ "$c" == "" ]; then
   break
fi

Here, the condition states that if the entered line is empty, the loop breaks. So, to finish your text entry, you have to press enter twice

2. Passing it to the variable so that it can be sent to the output

We now have the input. But we need to pass it to a variable in a proper format to use it effectively. Following line of code meets our requirements:

text+=$c$'\n'

It appends the line we typed in the current iteration and adds a newline character to the end of the string and appends the entire string to the "text" variable.

Once the input is finished, we have the complete string that we typed out in the variable "text". You can finally print it using echo or printf.
Note: make sure you enclose your variable within double quotes or else, your output stream ignores the newline characters and prints all the characters in a single line

Please find the complete code here:

#! /usr/bin/bash

echo "Enter Your Text here: "

text=""
while true
do
read c
  
if [ "$c" == "" ]; then
   break
fi

text+=$c$'\n'
done
echo "Your output is: "
echo "$text"

Hope this helped. :)