[linux] How to run a shell script on a Unix console or Mac terminal?

I know it, forget it and relearn it again. Time to write it down.

First, give permission for execution:-
chmod +x script_name

1. If script is not executable:-
   For running sh script file:-
   sh script_name
   For running bash script file:-
   bash script_name
2. If script is executable:-
   ./script_name

NOTE:-you can check if the file is executable or not by using 'ls -a'

The file extension .command is assigned to Terminal.app. Double-clicking on any .command file will execute it.

To start the shell-script 'file.sh':

sh file.sh

bash file.sh

Another option is set executable permission using chmod command:

chmod +x file.sh

Now run .sh file as follows:

./file.sh

For the bourne shell:

sh myscript.sh

For bash:

bash myscript.sh

If you want the script to run in the current shell (e.g. you want it to be able to affect your directory or environment) you should say:

. /path/to/script.sh

or

source /path/to/script.sh

Note that /path/to/script.sh can be relative, for instance . bin/script.sh runs the script.sh in the bin directory under the current directory.

Little addition, to run an interpreter from the same folder, still using #!hashbang in scripts.

As example a php7.2 executable copied from /usr/bin is in a folder along a hello script.

#!./php7.2
<?php

echo "Hello!"; 

To run it:

./hello

Which behave just as equal as:

./php7.2 hello

The proper solutions with good documentation can be the tools linuxdeploy and/or appimage, this is using this method under the hood.