Blender python file to convert an stl file into an obj file.

convert-stl-obj.py

#!/bin/python

import bpy
import sys

argv = sys.argv
argv = argv[argv.index("--") + 1:] # get all args after "--"

candidate_list = [item.name for item in bpy.data.objects if item.type == "MESH"]

# select them only.
for object_name in candidate_list:
  bpy.data.objects[object_name].select()

# remove all selected.
bpy.ops.object.delete()

stl_in = argv[0]
obj_out = argv[1]

bpy.ops.import_mesh.stl(filepath=stl_in, axis_forward='-Z', axis_up='Y')
bpy.ops.export_scene.obj(filepath=obj_out, axis_forward='-Z', axis_up='Y')