unison

Bidirectional file synchronisation tool. More information: https://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html.

unison path/to/directory_1 path/to/directory_2

unison path/to/directory_1 path/to/directory_2 -auto

unison path/to/directory_1 path/to/directory_2 -ignore pattern

unison -doc topics