Comparing the contents of two files in Sublime Text
There are a number of diff plugins available via Package Control. I've used Sublimerge Pro, which worked well enough, but it's a commercial product (with an unlimited trial period) and closed-source, so you can't tweak it if you want to change something, or just look at its internals. FileDiffs is quite popular, judging by the number of installs, so you might want to try that one out.
Compare Side-By-Side looks like the most convenient to me though it's not the most popular:
UPD: I need to add that this plugin can freeze ST while comparing big files. It is certainly not the best decision if you are going to compare large texts.
You can actually compare files natively right in Sublime Text.
- Navigate to the folder containing them through
Open Folder...
or in a project - Select the two files (ie, by holding Ctrl on Windows or ⌘ on macOS) you want to compare in the sidebar
- Right click and select the
Diff files...
option.