#	Using BREAK to change end-of ensemble (LASTTR) flags directly
#	This simply sets LASTTR=1 when espnum changes and 0 when it
#	is the same as in preceding trace. 

#	This achieves the same result as the next example


*call	break	trace	espnum	lasttr		# set break=1 whenever espnnum
						# (shot location in SEG-Y) changes