apt-cache

Search for a package in your current sources

$ apt-cache search [query]

$ apt-cache show [package]

$ apt-cache policy [package]

$ apt-cache depends [package]

$ apt-cache rdepends [package]

apt-cache [options] command [arguments]

apt-cache queries the local APT package cache to search for packages, display detailed package information, and analyze dependency relationships. It reads the package index files downloaded by apt update and provides fast, offline access to package metadata without contacting remote repositories.
Common operations include searching for packages by name or description, inspecting version and dependency details, checking installation policies, and listing reverse dependencies. The output is suitable for scripting and can help diagnose dependency conflicts or determine which repository provides a given package.

search query

Search for packages matching the query in names and descriptions

Show detailed information about a package

Show general information about a package

Show policy settings and installation status

Show dependencies for a package

Show reverse dependencies (packages that depend on this one)

List all package names in the cache

Show cache statistics

Show a short listing of every package in the cache

Print full records when searching

Only search package names, not descriptions

/etc/apt/sources.list

Main file listing configured package repositories.

Directory for additional repository source files.

Directory for package pinning and priority preferences.

This tool operates on the local cache; run apt update first to ensure the cache is current.

Part of the APT (Advanced Package Tool) suite developed for Debian-based systems in the late 1990s.

apt(8), apt-get(8), dpkg(1)