Task 1: Comments
In bash scripts, comments are used to add explanatory notes or disable certain lines of code. Create a bash script with comments explaining what the script does.
#!/bin/bash
# This script checks if a specified directory exists, and if it does,
# it creates a backup of the directory by copying it to a backup location.
# Define the source directory to be backed up
SOURCE_DIR="/path/to/source_directory" # Replace with the actual directory path
# Define the destination directory for the backup
BACKUP_DIR="/path/to/backup_directory" # Replace with the actual backup directory path
# Check if the source directory exists
if [ -d "$SOURCE_DIR" ]; then
# If the source directory exists, create a backup
echo "Source directory exists. Creating backup..."
# Use the cp command to copy the source directory to the backup directory
cp -r "$SOURCE_DIR" "$BACKUP_DIR"
# Print a success message
echo "Backup created successfully at $BACKUP_DIR"
else
# If the source directory does not exist, print an error message
echo "Error: Source directory does not exist."
fi
Task 2 : Echo
The echo command is used to display messages on the terminal. Create a bash script that uses echo to print a message of your choice.
#!/bin/bash
# This script prints a message to the terminal using the echo command.
# Define the message to be printed
MESSAGE="Hello, welcome to my bash script!"
# Use echo to print the message
echo "$MESSAGE"
Task 3 : Variables
Variables in bash are used to store data and can be referenced by their name. Create a bash script that declares variables and assigns values to them.
#!/bin/bash
# This script demonstrates how to declare variables and assign values to them in bash.
# Declare and assign values to variables
GREETING="Hello"
NAME="Ojas"
AGE=23
CITY="Mumbai"
# Print the values of the variables using echo
echo "$GREETING, my name is $NAME."
echo "I am $AGE years old."
echo "I live in $CITY."
Task 4: Using Variables
Now that you have declared variables, let's use them to perform a simple task. Create a bash script that takes two variables (numbers) as input and prints their sum using those variables.
#!/bin/bash
# This script takes two numbers as input and prints their sum.
# Declare variables and assign values to them
NUMBER1=5 # You can change this value
NUMBER2=10 # You can change this value
# Calculate the sum of the two numbers
SUM=$((NUMBER1 + NUMBER2))
# Print the sum
echo "The sum of $NUMBER1 and $NUMBER2 is: $SUM"
Task 5 : Using Built-in Variables
Bash provides several built-in variables that hold useful information. Create a bash script that utilizes at least three different built-in variables to display relevant information.
#!/bin/bash
# This script demonstrates the use of built-in variables in bash.
# Display the name of the script
echo "Script name: $0"
# Display the number of arguments passed to the script
echo "Number of arguments: $#"
# Display the current process ID
echo "Current process ID: $$"
# Display the user executing the script
echo "User executing the script: $USER"
# Display the current working directory
echo "Current working directory: $PWD"
Task 6 : Wildcards
Wildcards are special characters used to perform pattern matching when working with files. Create a bash script that utilizes wildcards to list all the files with a specific extension in a directory.
#!/bin/bash
# This script lists all files with a specific extension in a directory.
# Specify the directory to search (you can change this to any directory)
DIRECTORY="/path/to/directory" # Replace with the actual directory path
# Specify the file extension to look for
EXTENSION="txt" # Change this to the desired file extension
# Use wildcards to list all files with the specified extension in the directory
echo "Listing all .$EXTENSION files in the directory $DIRECTORY:"
ls "$DIRECTORY"/*.$EXTENSION
# Alternatively, you can use a loop to list the files
echo "Using a loop to list the files:"
for file in "$DIRECTORY"/*.$EXTENSION;
do
echo "$file"
done
Final Script
#!/bin/bash
# Declare variables and assign values to them
fname="Ojas"
lname="Jawale"
# Printing value of variable
echo "Hii, $fname $lname!!"
# Take input as in number and print sum of them
num1=5
num2=10
echo "Sum of $num1 and $num2 is: $((num1+num2))"
echo "Script $0 is running by user: $USER"
echo "Process ID is: $$"
# Output
Hii, Ojas Jawale!!
Sum of 5 and 10 is: 15
Script ./bash.sh is running by user: shuhari
Process ID is: 772
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