IME, a script is a custom utility and generally small (maybe <500 lines). It's a go-between for other programs, getting its input by running another program (l

IME, a script is a custom utility and generally small (maybe <500 lines). It's a go-between for other programs, getting its input by running another program (like ps or netstat), or it reads the state of the O/S (like /proc), or it reformats data for output or to prepare input to another program. Scripts are almost always written in an interpreted language (and their execution time is rarely important), and usually they don't handle faults robustly. Scripts are conveniences; hacks.