perl -MNetAddr::IP -e "$ip=new NetAddr::IP '189.10.136.129/27'; print 'net ',$ip,' mask ',$ip->mask,' first ',$ip->first,' last ',$ip->last"

net 189.10.136.129/27 mask 255.255.255.224 first 189.10.136.129/27 last 189.10.136.158/27