@fperez wrote an script which “Merge[s]/concatenate[s] multiple IPython notebooks into one.” I use it a lot. Evidently, other people do, too. In early 2016, he opened an issue to add the script as an nbconvert tool, but nothing came of it. However, he and @Carreau came up with good (i.e. unsurprising) semantics for metadata merging and notebook naming:

metadata = {}
for n in reversed(notebooks):

I don’t think it’s possible to implement the merger as a preprocessor. Preprocessors are stateless, so you can’t implement a reduce operation. Instead, I wrote (er, packaged up) this library as an nbstripoutput-like package . It fits in a Makefile script just fine.

Right now, only the basic (originally fperez’s) functionality is implemented. However, I’m going to follow kynan’s lead and slowly pull in functionality similar to his nbstripout package.