No, but most of Linux software can be run on other systems since most of them are portable.
Yes!On a hard disk of a computer multiple operating system can be installed and run.... Example is Ubantu and Windows Xp on a single computerAfter the installation of multiple operating systems your computer will ask you to select a operating system of your choice....
For any Unix or Linux based operating system, make the text file readable and executable and then invoke (call) it by the file name, which will execute the script.