in reply to
how do you install a perl app::someapp module in bash
I hope your first question is about installing your script in linux machine, so you could launch the script from any directory. For this, either you can change the $PATH bash variable in ~/.bashrc file, append it with the directory which your script exists or create a link to your script under any directory which already exists in $PATH.
For your second question to make the script executable, yes, you have to give it executable permission and don't forget to add the shabang inside the script.