Interpreted language, in order to run the code you must either have a *nix computer if it is Linux it will likely have bash installed.
On Windows later versions of Windows 10 have a unix subsystem which comes with bash. Or you may install cygwin or gitbash
# source in fn.sh
chmod +x fn.sh
./fn.sh
- http://tldp.org/LDP/Bash-Beginners-Guide/html/
- http://tldp.org/LDP/abs/html/ Advanced bash sripting guide
- https://www.gnu.org/software/bash/manual/