Python script to insert gcode commands before a layer

From time to time I need to insert a pause in gcode to change filament. It's a nuisance to manually edit gcode and have to count layers or search for "g1 z". So I wrote a simple python script to automate this and other similar things (e.g., inserting a temperature change). [Here](https://github.com/arpruss/miscellaneous-scad/blob/master/scripts/insert.py) it is (click on "Raw" to download).

USE AT YOUR OWN RISK.

You should first edit the script to change the parking command for pauses. I set X to -12, which should work for my DaVinci 1.0a (Repetier) printer.

The script is designed for gcode produced by Slic3r and my Repetier-based DaVinci 1.0a. You should examine the output the first few times yourself to make sure that you are happy with it and it works with your slicer/printer and isn't confused by preambles in detecting layers.


Here is how to run it:

python insert.py filename.gcode layerspec layercommands layerspec layercommands ...

The layers must be given i