Based on the information provided, here are some recommendations for useful comparison software on Ubuntu and how to use them:
1. Meld: Meld is a comparison tool developed based on Python. It supports comparison of folder and file contents. You can install Meld on Ubuntu using the following commands:
```
sudo apt-get update
sudo apt-get install meld
```
Once the installation is complete, you can start Meld by entering the `meld` command in the terminal. You can select two or three folders or files to compare in Meld and see the differences between them.
2. Nautilus Compare: Nautilus Compare is a comparison tool similar to BCompare. It provides a right-click menu function, making the comparison of files and folders more convenient. You can follow the steps below to install Nautilus Compare on Ubuntu:
- Open a terminal and execute the following command to add the PPA of Nautilus Compare:
```
sudo add-apt-repository ppa:boamaod/nautilus-compare
sudo apt-get update
```
- Then execute the following command to install Nautilus Compare:
```
sudo apt-get install nautilus-compare
```
If the `add-apt-repository` command fails due to network and other problems, you can access the download address of Nautilus Compare [ [3](https://blog.csdn.net/larphy/article/details/105804611)] Manually download the installation package for your Ubuntu version and use the `dpkg -i` command to install it.
After the installation is complete, you can select files or folders in the Nautilus file manager and perform comparison operations through the options in the right-click menu.
These are recommendations for some useful comparison software under Ubuntu and how to use them. You can choose the appropriate software to compare files and folders according to your needs.
And nautilus-compare is a free Ubuntu file comparison tool, similar to BCompare on the Windows platform. It is developed based on Python and can be used to compare the contents of folders and files, and supports binary comparison. You can install nautilus-compare by adding the appropriate software sources and using the command, or download it from the relevant website and install it manually. It provides a right-click menu function, making file comparison more convenient.