# apt-cache
# Query the APT cache

# Search for package PKG. Both package names and their descriptions are
# searched for a REGEX match; to avoid this behavior, you may use the `-n`
# flag, which will only look for a match in the package name.
apt-cache search 'PKG'

# Regarding the above, although multiple package names may not be specified, -
# it's possible to use ERE to easily and quickly get around this limitation.
# Here, all 3 packages (PKG1, PKG2, and PKG3) will be sought.
apt-cache search '(PKG1|PKG2|PKG3)'