sddstimeconvert input.sdds output.sdds -epoch=column,Time,year=TheYear,month=TheMonth,day=DayOfMonth,hour=HourOfDay
where TheYear, TheMonth, DayOfMonth, and HourOfDay are the names of the columns in the input file and Time is the column to be created containing the time-since-epoch.
sddstimeconvert [inputFile] [outputFile] [-pipe[=input][,output]]
[-breakdown={column | parameter},timeName[,year=newName]
[,julianDay=newName][,month=newName][,day=newName][,hour=newName][,text=newName]]
[-epoch={column | parameter},newName,year=name
[,julianDay=name | month=name,day=name],hour=name]
Year values must be the full four-digit year; e.g., year 99 is not 1999, but rather 99 AD.