Aumenta a verbosidade da saída. De acordo com o homem da duplicidade :
--verbosity level, -vlevel
Specify output verbosity level (log level). Named levels and corresponding values
are 0 Error, 2 Warning, 4 Notice (default), 8 Info, 9 Debug (noisiest).
level may also be
a character: e, w, n, i, d
a word: error, warning, notice, info, debug
The options -v4, -vn and -vnotice are functionally equivalent, as are the
mixed/upper-case versions -vN, -vNotice and -vNOTICE.
--verbosity info
funcionou para mim