How do I make this file.sh executable via double click?

Remove the extension altogether and then double-click it. Most system shell scripts are like this. As long as it has a shebang it will work.

By default, *.sh files are opened in a text editor (Xcode or TextEdit). To create a shell script that will execute in Terminal when you open it, name it with the “command” extension, e.g., file.command. By default, these are sent to Terminal, which will execute the file as a shell script.

You will also need to ensure the file is executable, e.g.:

chmod +x file.command

Without this, Terminal will refuse to execute it.

Note that the script does not have to begin with a #! prefix in this specific scenario, because Terminal specifically arranges to execute it with your default shell. (Of course, you can add a #! line if you want to customize which shell is used or if you want to ensure that you can execute it from the command line while using a different shell.)

Also note that Terminal executes the shell script without changing the working directory. You’ll need to begin your script with a cd command if you actually need it to run with a particular working directory. E.g. you can use cd "$(dirname "$0")" to set the current working directory to the directory where your shell script lies.

You can just tell Finder to open the .sh file in Terminal:

1. Select the file
2. Get Info (cmd-i) on it
3. In the "Open with" section, choose "Other…" in the popup menu
4. Choose Terminal as the application

This will have the exact same effect as renaming it to .command except… you don't have to rename it :)