apt-cache

Query the APT package cache

TLDR

Search for a package in your current sources

$ apt-cache search [query]

Search only in package names

$ apt-cache search --names-only [query]

Show information about a package

$ apt-cache show [package]

Show whether a package is installed and up to date

$ apt-cache policy [package]

Show dependencies for a package

$ apt-cache depends [package]

Show packages that depend on a particular package

$ apt-cache rdepends [package]

Show available versions in a table format

$ apt-cache madison [package]

SYNOPSIS

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.

PARAMETERS

search regex

Search for packages matching the POSIX regex in names and descriptions

show package

Show detailed package record for a package

showpkg package

Show general information including versions and dependencies

showsrc package

Show all source package records for a package

policy [package]

Show policy settings, installation status, and repository priorities

depends package

Show dependencies for a package

rdepends package

Show reverse dependencies (packages that depend on this one)

madison package

Show available versions in a tabular format

pkgnames [prefix]

List all package names in the cache, optionally filtered by prefix

stats

Show cache statistics

dump

Show a short listing of every package in the cache

unmet

Show a summary of all unmet dependencies in the cache

-f, --full

Print full package records when searching

-n, --names-only

Only search package names, not descriptions

-i, --important

Print only Depends and Pre-Depends relations (for use with depends and unmet)

--installed

Limit output to currently installed packages

--recurse

Make depends and rdepends recursive

CONFIGURATION

/etc/apt/sources.list

Main file listing configured package repositories.

/etc/apt/sources.list.d/

Directory for additional repository source files.

/etc/apt/preferences.d/

Directory for package pinning and priority preferences.

CAVEATS

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

HISTORY

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