Sets time to GMT (t or true), or local (f or false). The default is t.
An optional log or group label.
The usegmt command lets you set the time for the time and date strings of any log or group to Greenwich Mean Time or local time. If no label is specified, this command sets a global default value for all logs and groups. Any specific value always overrides the global definition, regardless of the order in the configuration file or when a command is sent.