listNames.f90

program testNames
implicit none
integer :: count
character(len=50), dimension(500000) :: AllNames

CALL getFileNames(AllNames, count)
WRITE(*,*) count

end program

subroutine getFileNames(names, counter)
implicit none
integer, intent(out) :: counter
character(len=50), dimension(500000), INTENT(OUT) :: names
character(len=50) :: tempStr = "", pwd=""
integer :: openErr, readErr, strLen
counter = 0
call system("ls -R > lsAll.out")
open(file="lsAll.out", unit=55, action="read", iostat=openErr)

do
	read(55,"(A)",iostat=readErr) tempStr
	if(readErr /= 0) then
		if(counter<10) WRITE(*,*) "can't open"
		exit
	end if
	if(tempStr(1:2) == "./") then ! its a dir
		pwd = TRIM(tempStr)
	else
		counter = counter + 1
		if(len_trim(trim(pwd)//trim(tempStr))<51) then
			names(counter) = (trim(pwd))//(trim(tempStr))
			write(*,*) trim(trim(pwd))//(trim(tempStr))
		end if
	end if
end do
close(unit=55)
call system("rm lsAll.out")
end subroutine