apt-cache --version (return code: 0)
apt 1.2.19 (amd64)
apt-cache --help (return code: 0)
apt 1.2.19 (amd64)
Usage: apt-cache [options] command
apt-cache [options] show pkg1 [pkg2 ...]
apt-cache queries and displays available information about installed
and installable packages. It works exclusively on the data acquired
into the local cache via the 'update' command of e.g. apt-get. The
displayed information may therefore be outdated if the last update was
too long ago, but in exchange apt-cache works independently of the
availability of the configured sources (e.g. offline).
Most used commands:
showsrc - Show source records
search - Search the package list for a regex pattern
depends - Show raw dependency information for a package
rdepends - Show reverse dependency information for a package
show - Show a readable record for the package
pkgnames - List the names of all packages in the system
policy - Show policy settings
See apt-cache(8) for more information about the available commands.
Configuration options and syntax is detailed in apt.conf(5).
Information about how to configure sources can be found in sources.list(5).
Package and version choices can be expressed via apt_preferences(5).
Security details are available in apt-secure(8).