Although most of the below have appeared in earlier posts I thought it would be good to list of common ones I use.
List running VM’s on a host
esxcli vm process list
List all the Virtual Machines on a VMware ESXi Host
vm-support -V
List all mounted scsi id’s
esxcfg-scsidevs -m
List all volumes
esxcfg-volume -l
Force mount a volume
esxcfg-volume -M or
Find certain words in vmkernel log
grep "vmkernel:" /var/log/messages | grep "keyword"
Find all VMs that have snapshots in ESX
find /vmfs/volumes/ -name "*delta*" -type f -print0 | xargs -0 du --human-readable --total
Find all VMs that have snapshots in ESXi
find /vmfs/volumes/ -name "*delta*" -type f -print0 | xargs -0 du -h
Restart VMware ESX Service Management Agents
service mgmt-vmware restart
Restart VMware ESXi Service Management Agents
/sbin/services.sh restart
List network cards in ESXi
esxcfg-nics -l
List all the vswitches
esxcfg-vswitch -l