> vpex -
Usage: vpex [-H] [-] [-help]
[if=] input file name
[of=] ouput file name
[-i ] a simple flag
[n= ] an integer input value
[s= ] a floating point input value
[xy=] input one or two integers
> vpex if=file1 of=file2
input file name is file1
output file name is file2
> vpex n=3 file1
input file name is file1
n= (integer argument) is 3
> vpex -i xy=2 n=1 -o file2
output file name is file2
Option -i has been selected
n= (integer argument) is 1
xy= (argument pair) 2 2
> vpex -H
Usage: vpex [-H] [if=<inputfile>] [of=<outputfile>] [-i] [n=<value>]
[s=<value>] [xy=<value>]
> vpex file1 -o file2 3 8 6
input file name is file1
output file name is file2
n= (integer argument) is 3
s= (float argument) is 8.000000
xy= (argument pair) 6 6
> vpex 3 8 6
input file name is 3
n= (integer argument) is 8
s= (float argument) is 6.000000
> vpex if= of=
input file name is
output file name is
> vpex n= s= xy=
n= (integer argument) is 0
s= (float argument) is 0.000000
xy= (argument pair) 0 0