Linux.com - https://www.linux.com/news/comparing-files-and-directories-diff-and-comm-linux-commands
There are a number of ways to compare files and directories on Linux systems. The diff, colordiff, and wdiff commands are just a sampling of commands that you’re likely to run into. Another is comm. The command (think “common”) lets you compare files in side-by-side columns the contents of individual files.