Both files contain the phonetic alphabet but the second file, alpha2, has had some further editing so that the two files are not identical. The order of the files on the command line determines which file diff considers to be the ‘first file’ and which it considers to be the “second file.” In the example below alpha1 is the first file, and alpha2 is the second file. Let’s dive right in and analyze two files. In this tutorial, we’re going to look at the most useful human-friendly ways to use diff. The diff command was designed to find differences between source code files and to produce an output that could be read and acted upon by other programs, such as the patch command. This can be used to open files and projects in Sublime Text, as well working as an EDITOR for unix tools, such as git and subversion.

If you keep that in mind you’ll find it easier to understand the output from diff. Let’s focus on some of the most common MacOS Terminal commands you need to be familiar with when you are mastering the Terminal. There are tons of commands that you can make use of.

The diff command compares two files and produces a list of the differences between the two. To be more accurate, it produces a list of the changes that would need to be made to the first file, to make it match the second file. To change the file location, you will use the Terminal command introduced below.

Mac edit text file in terminal