Some Zimbra Server Maintenance Command

i) Version Check:  

/opt/zimbra/bin/zmcontrol -v

or 

zmcontrol -v

ii) Zimbra service star/stop/status check:

maintenance                        Toggle maintenance mode

zmcontrol shutdown                Stop services

zmcontrol start                       Start services

zmcontrol startup                    Start services

zmcontrol status                     Display service status

zmcontrol stop                        Stop services

iii) To list all user accounts [domain.com is optional]:

zmprov -l gaa [domain.com]