DiffTo compare two files line by line.
It's pre-installed on Linux.
$ diff [OPTION]… FILES $ diff options dir1 dir2
A visual diff and merge tool for the GNOME Desktop.
$ sudo apt install meld [Debian/Ubuntu systems] $ sudo yum install meld [RHEL/CentOS systems] $ sudo dnf install meld [Fedora 22+]
Once you have installed it, search for “meld” in the Ubuntu Dash or Linux Mint Menu, in Activities Overview in Fedora or CentOS desktop and launch it.
You will see the Meld interface below, where you can choose file or directory comparison as well as version control view. Click on directory comparison and move to the next interface.
Select the directories you want to compare, note that you can add a third directory by checking the option “3-way Comparison”.
Once you selected the directories, click on “Compare”.