Package Management

Ubuntu / Debian

dpkg -i <package>                   # Install a package from local file
dpkg --get-selections               # Show the list of packages installed through apt-get
dpkg --get-selections | grep php    # ... filtering for some specific package keyword
dpkg -L <package>                   # List files delivered by a given <package>
dpkg -S <file>                      # List packages providing given file
dlocate <file>                      # ... fast version of dpkg -S and dpkg -L combined (require package dlocate)
dlocate -S <file>                   # ... fast version of dpkg -S (require package dlocate)
dlocate -L <keyword>                # ... fast version of dpkg -L (require package dlocate)
apt-cache search <keyword>          # Search package cache (package name and description) for given <keyword>

To add a repository, edit file /etc/apt/sources.list ou sources.list.d/, then apt-get update.