Combining multiple Txt files in multiple folders based on date

Combining multiple Txt files in multiple folders based on date

I have data in multiple folders: I have a folder for a unit that has
inside it 100 job files ( Job001, Job002.....Job100) inside each of these
is a txt file name abc.txt. I want to take each of these files and combine
into one continous large txt file.
Help if anyone can figure out the easyiest way to do this and repeat for
different units