The `dpkg` command can be used to probe the Linux environment for information about installed packages. Use the `-l` argument to list the installed packages. # Piping through `less` Here "less" is a simple text reader used to scroll through the list of packages in a new buffer that opens in the existing terminal window. The list will not be mixed with other terminal commands and output. Hit `'q'` to return to terminal prompt. See "man less" for more info. ``` dpkg -l | less ``` # Match on List To check whether a package is installed or not: ``` dpkg -l {package_name} dpkg -l vlc ``` # Piping through `grep` To check if the package is installed or not (for example, `vlc`). ``` dpkg -l | grep vlc ``` # Show the location of installed packages Show the location where the package is installed. The "-S" (capital S) stands for "search" ``` sudo dpkg -S {package_name} sudo dpkg -S skype ```