demo_system_rename Program

       program demo_system_rename
       use M_system, only : system_rename
       use M_system, only : system_remove
       use M_system, only : system_perror
       implicit none
       character(len=256) :: string
       integer            :: ios, ierr

       ! try to remove junk files just in case
       ierr=system_remove('_scratch_file_')
       write(*,'(a,i0)') 'should not be zero ',ierr
       call system_perror('*demo_system_rename*')
       ierr=system_remove('_renamed_scratch_file_')
       write(*,'(a,i0)') 'should not be zero ',ierr
       call system_perror('*demo_system_rename*')

       ! create scratch file to rename
       open(unit=10,file='_scratch_file_',status='new')
       write(10,'(a)') &
       & 'Test by renaming "_scratch_file_" to "_renamed_scratch_file_"'
       write(10,'(a)') 'IF YOU SEE THIS ON OUTPUT THE RENAME WORKED'
       close(10)
       ! rename scratch file
       ierr=system_rename('_scratch_file_','_renamed_scratch_file_')
       if(ierr.ne.0)then
          write(*,*)'ERROR RENAMING FILE ',ierr
       endif
       ! read renamed file
       open(unit=11,file='_renamed_scratch_file_',status='old')
       INFINITE: do
          read(11,'(a)',iostat=ios)string
          if(ios.ne.0)exit INFINITE
          write(*,'(a)')trim(string)
       enddo INFINITE
       close(unit=11)

       ! clean up
       ierr=system_remove('_scratch_file_')
       write(*,'(a,i0)') 'should not be zero ',ierr
       ierr=system_remove('_renamed_scratch_file_')
       write(*,'(a,i0)') 'should be zero ',ierr

       end program demo_system_rename