Mastering Ubuntu APT: Core Commands for Installing, Searching, and Cleaning Packages

1. Core Commands – The Three‑Step Workflow

Step 1: Refresh the package list

sudo apt update

This command contacts the configured servers to retrieve the latest package information; it does not install anything. Running it before any installation is recommended.

Step 2: Upgrade installed packages

sudo apt upgrade

The system lists upgradable packages and asks for confirmation (press Y). If dependency changes or held packages appear, review the output before proceeding, especially for kernel or driver updates.

Step 3: Install software

sudo apt install <package-name>

Multiple packages can be installed at once, e.g., sudo apt install git vim vlc.

2. Searching and Uninstalling

Search for packages

apt search <keyword>

Example: apt search python. Pipe the output to grep for better filtering.

Remove a package (keep config files)

sudo apt remove <package-name>

Purge a package (delete config files)

sudo apt purge <package-name>

Clean up unused dependencies

sudo apt autoremove

Running this periodically frees disk space.

3. PPA – Extending Your Repositories

Official repositories are stable but may contain older versions. Personal Package Archives (PPA) let you install newer releases, though they delegate part of system updates to third‑party maintainers. Prefer official sources when possible.

Example – installing the latest OBS Studio:

# Add the PPA
sudo add-apt-repository ppa:obsproject/obs-studio
# Refresh the list (Ubuntu may do this automatically)
sudo apt update
# Install OBS Studio
sudo apt install obs-studio

4. Switching Mirrors – Speeding Up Downloads

The default Ubuntu mirrors are overseas and can be slow for users in China. You can switch to domestic mirrors (e.g., Alibaba Cloud, Tsinghua, USTC).

GUI method (recommended)

Open "Software & Updates".

In the "Download from" dropdown, choose "Other..." → "China".

Click "Select Best Server"; the system will test speeds.

Select the fastest server and click "Choose Server".

Close the window; you will be prompted to reload the sources.

Command‑line method (advanced)

Edit /etc/apt/sources.list and replace the domain names with those of a domestic mirror. Beginners should prefer the GUI method because this involves modifying system files.

Mastering APT gives you the essence of Linux software management: a single line of command can replace downloading and running graphical installers.