This is a python script that flattens multiple .tex files.

Usage:

python flatten.py main.tex main_flattened.tex

The first argument is your main .tex file. The script recursively looks for "\input{...}" and "\include{...}" latex code and flattens .tex contents accordingly. The final flattened content is written to the .tex file specified as the second argument.

With flattened .tex files, we can now use latexdiff to diff your .tex files and produce nicely notated pdf.

Some helpful articles on the usage of latexdiff:

• http://emeryblogger.com/2011/01/14/diff-your-latex-files-with-latexdiff/
• https://www.sharelatex.com/blog/2013/02/16/using-latexdiff-for-marking-changes-to-tex-documents.html