Parameters (or command line arguments) are shell variables which carry
information pertaining to a command line.
To reference a parameter, the dollar sign is placed before a number
from 0 to 9.
The variable $0 is special and refers to the name of the
current program which would be csh if $0 was accessed at
the command line prompt.
While the number after the $ must be 9 or less, higher
numbered arguments can be accessed using the $argv[n], where
n is a positive integer.
To access the 11th command line argument the following variable would
be used $argv[11].
The - operator can be used in the same manner as it was for
array variables.
A shorthand version of the #argv variable is to simply enclose
the number in curly braces, ${11}.
Parameters may seem strange and useless, but there importance will
become evident in the sections on shell programming.