In program debugging, tracing control instructions that examine internal program states can be saved in a file and this file can be used to initialize the debugging environment when a program is loaded by a debugger. When a source program is modified because of bugs, however, source line numbers are also changed. It is therefore necessary to update the source line numbers in a tracing control instruction file according to the modifications in the source program. This paper proposes a solution by means of an automatic resumption mechanism that simplifies the debugging procedure from source modification to the beginning of the next debugging. While a programmer is creating an executable program using make after he has modified the program, the tracing control instruction file is updated automatically, so the programmer does not even have to think of updating them. This mechanism makes it very easy to resume debugging with the same debugging environment after program modification.