Meld - Visual diff and merge tool
https://meldmerge.org/

Meld helps you compare files, directories, and version controlled projects. It provides two- and three-way comparison of both files and directories, and has support for many popular version control systems.

Meld is a visual diff and merge tool targeted at developers. Meld helps you compare files, directories, and version controlled projects. It provides two- and three-way comparison of both files and directories, and has support for many popular version control systems.

Meld 是一个针对开发者的可视化差异和合并工具。Meld 帮助你比较文件、目录和版本控制项目。它提供文件和目录的双向和三向比较，并支持许多流行的版本控制系统。

1. Installation

sudo apt-get update
sudo apt-get install meld

strong@foreverstrong:~$ sudo apt-get update
[sudo] password for strong: 
...                                                                                                                                
Reading package lists... Done
strong@foreverstrong:~$ 
 
strong@foreverstrong:~$ sudo apt-get install meld
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libllvm4.0 linux-headers-4.10.0-40 linux-headers-4.10.0-40-generic linux-headers-4.10.0-42 linux-headers-4.10.0-42-generic linux-headers-4.13.0-26
  linux-headers-4.13.0-26-generic linux-headers-4.13.0-31 linux-headers-4.13.0-31-generic linux-headers-4.13.0-32 linux-headers-4.13.0-32-generic linux-headers-4.13.0-36
  linux-headers-4.13.0-36-generic linux-headers-4.13.0-37 linux-headers-4.13.0-37-generic linux-headers-4.13.0-38 linux-headers-4.13.0-38-generic linux-headers-4.13.0-39
  linux-headers-4.13.0-39-generic linux-image-4.10.0-40-generic linux-image-4.10.0-42-generic linux-image-4.13.0-26-generic linux-image-4.13.0-31-generic
  linux-image-4.13.0-32-generic linux-image-4.13.0-36-generic linux-image-4.13.0-37-generic linux-image-4.13.0-38-generic linux-image-4.13.0-39-generic
  linux-image-extra-4.10.0-40-generic linux-image-extra-4.10.0-42-generic linux-image-extra-4.13.0-26-generic linux-image-extra-4.13.0-31-generic
  linux-image-extra-4.13.0-32-generic linux-image-extra-4.13.0-36-generic linux-image-extra-4.13.0-37-generic linux-image-extra-4.13.0-38-generic
  linux-image-extra-4.13.0-39-generic linux-signed-image-4.10.0-40-generic linux-signed-image-4.10.0-42-generic linux-signed-image-4.13.0-26-generic
  linux-signed-image-4.13.0-31-generic linux-signed-image-4.13.0-32-generic linux-signed-image-4.13.0-36-generic linux-signed-image-4.13.0-37-generic
  linux-signed-image-4.13.0-38-generic linux-signed-image-4.13.0-39-generic
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  python-gi python-gi-cairo
The following NEW packages will be installed:
  meld python-gi python-gi-cairo
0 upgraded, 3 newly installed, 0 to remove and 122 not upgraded.
Need to get 657 kB of archives.
After this operation, 3,701 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://cn.archive.ubuntu.com/ubuntu xenial/main amd64 python-gi amd64 3.20.0-0ubuntu1 [194 kB]
Get:2 http://cn.archive.ubuntu.com/ubuntu xenial/universe amd64 python-gi-cairo amd64 3.20.0-0ubuntu1 [6,246 B]
Get:3 http://cn.archive.ubuntu.com/ubuntu xenial/universe amd64 meld all 3.14.2-1 [457 kB]
Fetched 657 kB in 2s (243 kB/s)
Selecting previously unselected package python-gi.
(Reading database ... 588993 files and directories currently installed.)
Preparing to unpack .../python-gi_3.20.0-0ubuntu1_amd64.deb ...
Unpacking python-gi (3.20.0-0ubuntu1) ...
Selecting previously unselected package python-gi-cairo.
Preparing to unpack .../python-gi-cairo_3.20.0-0ubuntu1_amd64.deb ...
Unpacking python-gi-cairo (3.20.0-0ubuntu1) ...
Selecting previously unselected package meld.
Preparing to unpack .../archives/meld_3.14.2-1_all.deb ...
Unpacking meld (3.14.2-1) ...
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) ...
Processing triggers for shared-mime-info (1.5-2ubuntu0.1) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for libglib2.0-0:amd64 (2.48.2-0ubuntu1) ...
Processing triggers for gnome-menus (3.13.3-6ubuntu3.1) ...
Processing triggers for desktop-file-utils (0.22-1ubuntu5.1) ...
Processing triggers for bamfdaemon (0.5.3~bzr0+16.04.20160824-0ubuntu1) ...
Rebuilding /usr/share/applications/bamf-2.index...
Processing triggers for mime-support (3.59ubuntu1) ...
Setting up python-gi (3.20.0-0ubuntu1) ...
Setting up python-gi-cairo (3.20.0-0ubuntu1) ...
Setting up meld (3.14.2-1) ...
strong@foreverstrong:~$ 

2. Meld Diff Viewer

3. Lock to Launcher

References

[1] Yongqiang Cheng, https://yongqiang.blog.csdn.net/