Apt-cache

apt-cache is a part of the apt suite of tools used to manage packages in the Debian distribution. apt-cache is a tool for sifting through package information that resides on your computer after doing

Examples
Search for a package using a keyword: apt-cache search mp3 This will search for packages that have "mp3" in the name or description.

Show package details: apt-cache show mpg123''' This shows package information about a package named "mpg123". It will display things such as the package dependancies, the long description, the version, the installed size, etc.