DIFF utility works for 2 files. How to compare more than 2 files at a time?
Displaying 10 files side-by-side and highlighting differences can be easily done with Diffuse. Simply specify all files on the command line like this: diffuse 1.txt 2.txt 3.txt 4.txt 5.txt 6.txt 7.txt 8.txt 9.txt 10.txt