Cleaning Up Ubuntu System: Detailed Explanation of the `apt autoremove` Command

After installing and uninstalling software in Ubuntu, residual unnecessary dependency packages often remain, occupying disk space and bloating the system. `apt autoremove` can automatically clean up these "useless automatic dependencies"—packages that were "incidentally" installed to satisfy dependencies when software was installed but are no longer required by any other software. This command requires administrative privileges, with the basic syntax being `sudo apt autoremove`. After execution, it will prompt for the packages to be removed and the space to be freed; enter `y` to confirm. Optional flags include `-y` for automatic confirmation (recommended to check risks without parameters first) or `--purge` to remove configuration files (not the default behavior). Distinct from `apt clean` (clears cache) and `remove` (removes packages without dependencies), `autoremove` focuses specifically on cleaning useless dependencies. Before use, simulate checks with `--dry-run` to avoid frequent operations. It is safer to run after updating the software sources, and `-y` should be used cautiously to prevent accidental deletions. Regular use can free up disk space, and mistakenly removed dependencies can be reinstalled to restore functionality.