In the following post, you will unleash the power of “while Loops” with Real-Time Use Cases in bash.
Syntax of while loop:
while [ condition ]; do # Commands to be executed as long as the condition is true done
Here are the steps to create a simple Bash script that uses a while loop to count down from 10 to 1 in bash.
Create a new file as mentioned below.
countdown_script.sh
Copy and paste below simple Bash script that uses a while loop to count down from 10 to 1.
#!/bin/bash # Set the initial value of the countdown countdown=10 # Start a while loop that continues as long as the countdown is greater than 0 while [ $countdown -gt 0 ]; do # Print the current value of the countdown echo "Countdown: $countdown" # Decrement the countdown by 1 ((countdown--)) # Optional: Add a delay of 1 second (sleep 1) between each iteration sleep 1 done # Print a message when the countdown reaches 0 echo "Countdown completed!"
Here’s a breakdown of the script:
1. #!/bin/bash: This is called a shebang and specifies the path to the interpreter (in this case, Bash).
2. countdown=10: Initializes a variable named countdown with the value 10.
3. while [ $countdown -gt 0 ]; do: Starts a while loop that continues as long as the value of countdown is greater than 0.
4. echo “Countdown: $countdown”: Prints the current value of countdown to the terminal.
5. ((countdown–)): Decrements the value of countdown by 1.
6. sleep 1: Adds an optional delay of 1 second between each iteration of the loop (you can remove this line if you don’t want a delay).
7. done: Marks the end of the while loop.
8. echo “Countdown completed!”: Prints a message indicating that the countdown has been completed.
Make the script executable by running the following command in the terminal:
chmod +x countdown_script.sh
Then, you can run the script using:
./countdown_script.sh
This script will count down from 10 to 1, printing each countdown value and waiting for 1 second between each iteration.
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