This is more or less the findings from the comments of https://unix.stackexchange.com/a/556038 and my answer at https://unix.stackexchange.com/a/556303: While "aptitude -v moo" to "aptitude -vvvvvv moo" works as expected and—as Stephen Kitt (X-Debbugs-Cc'ed) mentioned—also setting "Aptitude::CmdLine::Verbose" in the config file works, e.g. "aptitude -o Aptitude::CmdLine::Verbose=6 moo" (nor any other value I tried, e.g. 2 or 5) works as if not a single "-v" has been specified, i.e. seems to be ignored. Since many other combinations of "aptitude -o <key=value> <subcommand>" work fine (I use them daily in aliases), and "aptitude -o Aptitude::CmdLine::Verbose=2 update" is not as verbose as "aptitude -v update" is (see https://unix.stackexchange.com/a/556303), I suspect there is a bug in parsing specifically the "Aptitude::CmdLine::Verbose" option when given on the commandline via "-o".