How to join two binary files on Windows

I didn't initially notice that the question was for Cygwin, Here is a solution for DOS anyway (not Cygwin).

Open a command prompt and type COPY /?

COPY lets you concatenate files by using the + operator

It also lets you designate them as binary by using the /B operator

So if you change to the directory with CD MyDir and run the following I would expect your concatentated file to be created

 COPY /B File1.bin + File2.bin file3.bin

To join two (or more) binary files together, the syntax is:

copy file1/b+file2/b file3/b

I use an a DOS or CMD window in an old XP machine to join two 100KB files together, and its almost instant.