{HEAD ~ The saved state} and {TAIL ~ commands} can be used for analysis, such as by processing only a subset of the commands or processing a modified set of the commands 
{ HEAD ~ The saved state } and { TAIL ~ commands } can be used for analysis , such as by processing only a subset of the commands or processing a modified set of the commands
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH