System Maintenance: Clearing Cached Files with Ubuntu apt clean

In the Ubuntu system, packages downloaded by the `apt` tool are temporarily stored in the cache directory `/var/cache/apt/archives/`. Long-term accumulation of these packages can occupy disk space and affect system speed. Cleaning the cache can improve efficiency, and the `apt clean` command is recommended for this purpose. APT cache is used to accelerate repeated installations and is stored in the specified directory. The problems of long-term non-cleaning include occupying space and containing useless old version packages. To use `apt clean`, open the terminal (Ctrl+Alt+T), execute `sudo apt clean`, and enter the administrator password. After cleaning, it will not affect the installed software. Other related commands: `autoclean` only cleans up old version packages (retains new versions); `autoremove` deletes packages that are no longer dependent (not for cleaning cache). Precautions: Clean regularly (e.g., monthly), and you can check the cache size with `du -sh /var/cache/apt/archives/`. Combining with `autoclean` or `autoremove` can enable fine-grained management of the cache and keep the system clean.