Shell Script Practical Interview Questions

1. write a shell script to read user input as a string an in output it will reverse the string

Ans:

#!/bin/bash

# Prompt the user to enter a string
read -p "Enter a string to reverse: " input

# Reverse the string and print it
reversed=$(echo "$input" | rev)

echo "Reversed string: $reversed"

2. Write a shell script to reverse a given string

Ans:

#!/bin/bash

input="ashwini"

reverse_string() {
    local str="$1"
    local reversed=""
    local length=${#str}
    local i

    # Loop through the string from end to start
    for ((i=length-1; i>=0; i--)); do
        reversed="${reversed}${str:$i:1}"
    done

    echo "$reversed"
}

# Call the function with the predefined string and display the reversed string
reversed=$(reverse_string "$input")

echo "Original string: $input"
echo "Reversed string: $reversed"

3. Write a shell script to check website is accessible or not

Ans:

a. Using Curl

#!/bin/bash

# URL to check
url="http://example.com"

# Perform the HTTP request and check if the website is accessible
response=$(curl --write-out "%{http_code}" --silent --output /dev/null "$url")

# Check the response code
if [ "$response" -eq 200 ]; then
    echo "The website $url is accessible."
else
    echo "The website $url is not accessible. HTTP status code: $response"
fi

b. Using wget

#!/bin/bash

# URL to check
url="http://example.com"

# Perform the HTTP request and check if the website is accessible
wget --spider "$url" 2>/dev/null

# Check the exit status
if [ $? -eq 0 ]; then
    echo "The website $url is accessible."
else
    echo "The website $url is not accessible."
fi

4. write a shell script to find number of alphabets (Both uppercase and lowercase) in a given document

Ans:

#!/bin/bash

# Check if a file name was provided
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 filename"
    exit 1
fi

# Get the filename from the argument
file="$1"

# Check if the file exists
if [ ! -f "$file" ]; then
    echo "File not found!"
    exit 1
fi

# Count the number of alphabetic characters (both uppercase and lowercase)
alphabet_count=$(grep -o '[a-zA-Z]' "$file" | wc -l)

# Display the result
echo "Number of alphabetic characters in $file: $alphabet_count"

5. write a shell script only count uppercase letter in given document

Ans:

#!/bin/bash

# Check if a file name was provided
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 filename"
    exit 1
fi

# Get the filename from the argument
file="$1"

# Check if the file exists
if [ ! -f "$file" ]; then
    echo "File not found!"
    exit 1
fi

# Count the number of uppercase alphabetic characters
uppercase_count=$(grep -o '[A-Z]' "$file" | wc -l)

# Display the result
echo "Number of uppercase letters in $file: $uppercase_count"

6. Write a shell script to count how much numbers in a given file

Ans:

#!/bin/bash

# Check if a file name was provided
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 filename"
    exit 1
fi

# Get the filename from the argument
file="$1"

# Check if the file exists
if [ ! -f "$file" ]; then
    echo "File not found!"
    exit 1
fi

# Count the number of numeric characters (0-9)
number_count=$(grep -o '[0-9]' "$file" | wc -l)

# Display the result
echo "Number of numeric characters in $file: $number_count"

7. Shell script count no. of s in Mississippi

x="mississippi"
grep -o "s" <<<"$x" | wc -l

8. Write a shell script to check number is +ve or -ve

    #!/bin/bash
   
    # 1. Prompt user to enter a number
    echo "Enter a number:"
    read num
   
    # Check if the number is positive, negative, or zero
    if [ $num -gt 0 ]; then
      echo "The number is positive."
    elif [ $num -lt 0 ]; then
      echo "The number is negative."
    else
      echo "The number is zero."
    fi
   

   9. Write a shell script to list a fruits in given array

#2. Using a for loop to iterate over a list of items:**

    #!/bin/bash
    # Define a list of fruits
    fruits=("Apple" "Banana" "Orange" "Grapes" "Watermelon")
    # Iterate over the list of fruits using a for loop
    echo "List of fruits:"
    for fruit in "${fruits[@]}"
    do
     echo "$fruit"
    done

Output:

List of fruits:

Apple

Banana

Orange

Grapes

Watermelon