Did you ever start a program/command from the command line (shell, terminal)?
If you perform a copy, you call a program with 2 parameters, the source and the target:
a.txt is the first and b.txt the second parameter.
In a java-Program you get parameters with 'args':
'args' is of course a random name, just conventional named 'args'.
You ask the array for its length and iterate over the content if you need to. In the shell, the arguments are $1, $2, $... and $# is the number of arguments; a starting point:
Here is an in deep guide to bash-scripting:
http://tldp.org/LDP/abs/html/
Feel free if you still have questions, but try for yourself, read your material, do your etudes.
