-format tracefile. It has three commandline parameters, the first is tracefile
-name, the second is a number (number of cpu), the last one is root directory
-for the new trace (this can be omitted, by default it is 'foo')
+format tracefile. It has several commandline parameters, the first is process file
+name, the second is a number (the number of cpu in the machine), the third is
+the first tracefile name(corresponding to the first cpu), the fourth is the
+second tracefile name(corresponding to the second cpu), the fifth is ...,
+the last one is root directory for the new trace (this can be omitted,
+by default it is 'foo')