The FILE specifier indicates the name of the file to be connected to the unit. It takes the following form:
FILE = name
The name can be any pathname allowed by the operating system.
Any trailing blanks in the name are ignored.
If FILE is omitted and the unit is not connected to a file, the OPEN
statement must specify STATUS='SCRATCH'.
If the file name is stored in a numeric scalar or array, the name
must consist of ASCII characters terminated by an ASCII null
character (zero byte). However, if it is stored in a character
scalar or array, it must not contain a zero byte.