ARGS is an executable FORTRAN90 program that demonstrates command line argument retrieval.
In particular, ARGS is a demonstration of the IARGC and GETARG routines, commonly available on UNIX systems.
These routines allow a FORTRAN program to count and retrieve the command line arguments with which it was invoked. Thus, if an executable program is called fu and we invoke it with the command
fu man chuthen IARGC will return the value 2, and GETARG, with an input of 0, 1 or 2, will return the values fu, man or chu.
ARGS is also available in a C version and a C++ version and a FORTRAN77 version and a MATLAB version.
GFORTRAN_INTRINSICS is a FORTRAN90 program which demonstrates the use of intrinsic programs provided by the GFORTRAN compiler, which include versions of IARGC and GETARG.
You can go up one level to the FORTRAN90 source codes.