Bug fix: append to `ishape_last.txt` if exist

Inst_eddies/inst_eddies.f90

@@ -204,9 +204,9 @@ program inst_eddies
      end if
   end do
 
-  call write_aux(corner_deg, step_deg, nlon, nlat, hshpc_cyclo, &
+  call write_aux(corner_deg, step_deg, nlon, nlat, hshpc_cyclo, exist, &
        shpc_dir = "SHPC_cyclo")
-  call write_aux(corner_deg, step_deg, nlon, nlat, hshpc_anti, &
+  call write_aux(corner_deg, step_deg, nlon, nlat, hshpc_anti, exist, &
        shpc_dir = "SHPC_anti")
   CALL shpc_close(hshpc_cyclo)
   CALL shpc_close(hshpc_anti)

Inst_eddies/write_aux.f90

@@ -4,7 +4,7 @@ module write_aux_m
 
 contains
 
-  subroutine write_aux(corner_deg, step_deg, nlon, nlat, hshpc, shpc_dir)
+  subroutine write_aux(corner_deg, step_deg, nlon, nlat, hshpc, exist, shpc_dir)
 
     ! Write auxiliary files "grid_nml.txt" and "ishape_last.txt".
 
@@ -30,6 +30,7 @@ contains
     ! the grid is global
 
     TYPE(shpc), intent(in):: hshpc
+    logical, intent(in):: exist
     character(len = *), intent(in):: shpc_dir
 
     ! Local:
@@ -45,10 +46,18 @@ contains
     write(unit, nml = grid_nml)
     close(unit)
 
-    open(unit, file = shpc_dir // "/ishape_last.txt", status = "replace", &
-         action = "write")
-    write(unit, fmt = *) n_entities - 1
-    close(unit)
+
+    if (exist) then
+       open(unit, file = shpc_dir // "/ishape_last.txt", status = "old", &
+            action = "write", position = "append")
+       write(unit, fmt = *) n_entities - 1
+       close(unit)
+    else
+       open(unit, file = shpc_dir // "/ishape_last.txt", status = "replace", &
+            action = "write")
+       write(unit, fmt = *) n_entities - 1
+       close(unit)
+    end if
 
   end subroutine write_aux