perl project command line arg?

[inked]

hi ive got this assignment to do, ive got to write a perl program that analyses a text file to obtain statistics. Need some help with this particular section

when run the program should check if an argument has been provided if not the program should prompt for and accept input of a file name from the keyboard

i assume this has something to do with command line arguments however im finding it hard to find any sort of reference, the materials i have arent all that brilliant on how to properly code this for starters not even sure im looking in the right place

[Salem]

http://www.perl.org/ and a Camel Book

First thing you need to search for is all about the array @ARGV

[mitchems]

Personally if these arguments are operators or switches I like to use Get::Opts which converts the operators to $opt_[letter] and can get switches as well as values.