prune_restart_files Subroutine

   subroutine prune_restart_files(params, restart_dir)
      type(case_params_t), intent(in) :: params
      character(len=*), intent(in) :: restart_dir

      integer :: exitstat, first_to_delete
      character(len=32) :: first_to_delete_text
      character(len=3*path_len + 256) :: command

      if (params%restart_keep <= 0) return

      ! Keep the most recently written restart files in this restart directory.
      ! This mirrors the existing POSIX-shell style used for output directory
      ! creation; paths with spaces are not supported elsewhere in the solver.
      first_to_delete = params%restart_keep + 1
      write(first_to_delete_text, '(i0)') first_to_delete
      command = 'if ls ' // trim(restart_dir) // '/restart_*.rst >/dev/null 2>&1; then ' // &
                'ls -1t ' // trim(restart_dir) // '/restart_*.rst | tail -n +' // &
                trim(adjustl(first_to_delete_text)) // ' | xargs -r rm -f; fi'
      call execute_command_line(trim(command), exitstat=exitstat)
      if (exitstat /= 0) call fatal_error('restart', 'failed pruning old restart files in: '//trim(restart_dir))
   end subroutine prune_restart_files