### 8.100 `GET_COMMAND_ARGUMENT` — Get command line arguments

Description:
  Retrieve the NUMBER-th argument that was passed on the command line when the containing program was invoked.
Standard:
  Fortran 2003 and later
Class:
  Subroutine
Syntax:
  `CALL GET_COMMAND_ARGUMENT(NUMBER [, VALUE, LENGTH, STATUS])`
Arguments:

  NUMBER | Shall be a scalar of type `INTEGER` and of default kind, NUMBER \geq 0
  VALUE | (Optional) Shall be a scalar of type `CHARACTER` and of default kind.
  LENGTH | (Optional) Shall be a scalar of type `INTEGER` and of default kind.
  STATUS | (Optional) Shall be a scalar of type `INTEGER` and of default kind.

Return value:
  After `GET_COMMAND_ARGUMENT` returns, the VALUE argument holds the NUMBER-th command line argument. If VALUE can not hold the argument, it is truncated to fit the length of VALUE. If there are less than NUMBER arguments specified at the command line, VALUE will be filled with blanks. If NUMBER = 0, VALUE is set to the name of the program (on systems that support this feature). The LENGTH argument contains the length of the NUMBER-th command line argument. If the argument retrieval fails, STATUS is a positive number; if VALUE contains a truncated command line argument, STATUS is -1; and otherwise the STATUS is zero.
Example:

                PROGRAM test_get_command_argument
                  INTEGER :: i
                  CHARACTER(len=32) :: arg

                  i = 0
                  DO
                    CALL get_command_argument(i, arg)
                    IF (LEN_TRIM(arg) == 0) EXIT

                    WRITE (*,*) TRIM(arg)
                    i = i+1
                  END DO
                END PROGRAM

See also:
  GET_COMMAND, COMMAND_ARGUMENT_COUNT