A scripting language is a vocabulary and syntax for giving instructions to a computer, just like a programming language. The differences between the two are largely aesthetic, to the point that people often differ on whether a particular language is a programming language or a scripting language (Perl is an excellent example). Scripting languages tend to be "lighter" (easier to use, at the cost of memory).

Scripting languages (Perl) are very often interpreted--translated into machine code while running--as opposed to compiled--turned into an executable once, which can then be run more quickly. That feature makes it easier or unnecessary to port scripts to new systems, but again, at a greater efficiency cost.

Perl is a gray area because it contains aspects of both scripting and programming languages. It's full-featured, and expandable to make that even more so. It's also possible to compile Perl programs, but they're more typically interpreted. The purpose of Perl also comes into play--it's used both for very light utilities, much in the same way as bash, but at the same time, it's extremely popular for programming websites.