Apt-file is a Debian® command that relates to the advanced packaging tool (APT). The main uses of the command are related to examining the file contents of packages. In this context, packages are sets of files held in repositories that can be obtained remotely and installed on a local machine. The main benefit of apt-file is that the file contents of these packages may be examined without actually downloading or installing anything, which can save on time and bandwidth. Apt-file may be used to search for a particular file among all packages, or to examine the contents of a single package.
The advanced packaging tool is an interface that may be used to obtain, examine, and install software on Debian® and other related operating systems (OSes). Debian® is an operating system that uses the Linux kernel and OS tools from GNU's Not Unix (GNU). Many Debian® variants, such as Ubuntu® and Knoppix®, may also make use of the advanced packaging tool and its related commands.
Debian® and derivative OSes operate mainly under the GNU General Public License (GPL), and the official software repositories typically contain programs that are also GPL compliant. When apt-file is installed, it is typically ran with the syntax apt-file update to build a local list of all packages in the official repositories. Additional repositories may also be added manually, providing access to packages that may contain drivers and other proprietary code that does not necessarily conform to GPL. The advanced packaging tool may then be used to search the files of these packages as well as install or uninstall them, just like those from the official sources.
One of the main benefits of apt-file is its ability to work remotely. Once an update has been ran to renew the list of packages, the command may be used to search the file contents of any or all packages. This can be useful if a particular file is required, as it may be located and obtained without the need to download multiple packages during the search. The apt-file command can also be useful to examine local packages. Since the command can list the file contents of any package, it may be used to locate missing files so that they can be obtained.
Apt-file is traditionally ran from a command line in a terminal window, though certain front end graphical user interfaces (GUIs) may be used instead. If a user is new to Linux or uncomfortable using the terminal, a GUI can provide an easy way to use the various advanced packaging tool commands. These GUIs may be used to search files, manage installations, or for other more advanced purposes.