Create And Run A Script

Now that you understand what a shell script is, let's create one and run it. The process involves three steps: creating the file, making it executable, and running it.

First, create a new file with a .sh extension. You can use echo with redirection to write the shebang and commands:

echo '#!/bin/bash' > greet.sh
echo 'echo "Hello, World!"' >> greet.sh

Before you can run the script, you need to give it execute permission. By default, new files don't have this permission. Use chmod to add it:

chmod +x greet.sh

Now you can run the script by specifying its path. For a script in your current directory, use ./ before the filename:

./greet.sh

This outputs Hello, World!. The ./ tells the shell to look in the current directory rather than searching the PATH. Without it, the shell won't find your script.

You can also run a script without execute permission by calling the interpreter directly:

bash greet.sh

This explicitly tells Bash to interpret the file, bypassing the need for execute permission.