64.Break_And_Continue.md

Break Statement

• The break statement is used to terminate the loop execution prematurely based on a specific condition.

---

Example 1: Breaking a Loop at a Certain Condition

#!/bin/bash
i=1
while [ "$i" -le 10 ]
do
  if [ "$i" -eq 5 ]; then
    break
  fi
  echo "$i"
  i=$((i + 1))
done

Output:

1
2
3
4

Explanation:

• The loop iterates from 1 to 10, but when the value of i reaches 5, the break statement terminates the loop.

---

Example 2: Real-Time Digital Clock with Exit Condition

#!/bin/bash
while [ true ]
do
  clear
  printf "\n\n\n\n\n\n\t\t\t\t$(date +%H:%M:%S)"
  sleep 1
  h=$(date +%H)
  m=$(date +%M)
  if [ "$h" -eq 20 ] && [ "$m" -eq 35 ]; then
    break
  fi
done

Explanation:

• This script displays a real-time digital clock.
• The break statement stops the script when the system clock reaches 20:35 (8:35 PM).

---

Notes:

1. Condition Groups: Use [ condition ] with -a or && for combining conditions.
2. clear Command: Clears the terminal for a clean display during each iteration.
3. sleep Command: Pauses the loop for 1 second to update the clock.

---

Continue Statement

The continue statement is used to skip the current iteration of a loop and continue with the next iteration.

Example 1:

#! /bin/bash
i=0
while [ $i -lt 10 ]
do
 let i++
 if [ $((i%2)) -eq 0 ]; then
   continue
 fi
 echo $i
done

Output:

1
3
5
7
9

Script to Read File Name and Display its Content

This script reads a file name from the user, checks if the file exists, and displays its content. It also allows the user to display the content of another file or exit the program.

#! /bin/bash
while [ true ]
do
    read -p "Enter File Name to Display content: " fname
    # Checking whether the file exists or not and whether it's a regular file
    if [ -f $fname ]; then
        echo "The content of $fname:"
        echo "----------------------"
        cat $fname
    else
        echo "$fname does not exist"
    fi
    
    read -p "Do you want to display content of another file [Yes|No]: " option
    case $option in
        [yY]|[Yy][eE][sS])
            continue
            ;;
        [nN]|[nN][oO])
            break
            ;;
    esac
done

echo "Thanks for using the application"

Explanation:

• The script continuously asks the user for a file name and checks whether it exists. If the file exists, it displays its content using cat.

• After displaying the content, it asks whether the user wants to check another file. If the user types "Yes" or "y" (in various forms), the loop continues with the continue statement. If the user types "No" or "n", the loop breaks, and the program exits.

• If the file doesn't exist, the script notifies the user and asks again.

• Use of continue to skip the next iteration and break to exit the loop based on user input.

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1. Write a Script that Reads a String as Input and finds its Reverse?

2. Write a Script that performs Reverse of a given String?

#! /bin/bash
read -p "Enter any string to find reverse: " str   # Step 1: Read input string
len=$( echo -n $str | wc -c )   # Step 2: Calculate the length of the string
output=""  # Step 3: Initialize an empty string to store the reversed string

while [ $len -gt 0 ]   # Step 4: Loop until the length becomes 0
do
    ch=$( echo -n $str | cut -c $len )   # Step 5: Extract the character at the current position
    output=$output$ch   # Step 6: Append the character to the output string
    let len--   # Step 7: Decrement the length by 1 to move to the previous character
done

echo "The Original String: $str"   # Step 8: Print the original string
echo "The Reversed String: $output"   # Step 9: Print the reversed string