Via Runtime Arguments and GETARG

The library routine getarg(3F) can be used to read the command-line arguments at runtime into a character variable. The argument is interpreted as a file name and used in the OPEN statement FILE= specifier:

demo% cat testarg.f
         CHARACTER outfile*40
C  Get first arg as output file name for unit 51
         CALL getarg(1,outfile)
         OPEN(51,FILE=outfile)
         WRITE(51,*) 'Writing to file: ', outfile
         END
demo% f77 -silent -o tstarg testarg.f
demo% tstarg AnyFileName
demo% cat AnyFileName
 Writing to file: AnyFileName
demo%