Always start your script with #!/bin/bash. That first line is called a shebang (#!). It tells Linux which program should run the script. Without it, your script might not run correctly. Example: #!/bin/bash echo "Hello, world!" Steps to run it: Save it as hello.sh. Make it executable: chmod +x hello.sh Run it: ./hello.sh Output: Hello, world! 👉 Without the #!/bin/bash line, Linux will use the shell of the session you are logged into.