9. A computer program product comprising a computer readable storage device storing program instructions for execution by a processor, the program instructions comprising: program instructions for controlling execution of an executable instruction stream that invokes a sequence of high-level procedures automatically and without user intervention, wherein the executable instruction stream is a binary instruction stream and the invocation of the sequence of high-level procedures is a sequence of function calls performed by the executable instruction stream; and program instructions for generating a trace file during execution of the executable instruction stream that represents invocations of the high-level procedure invocations as a human-readable script that can be executed to repeat the invocation of the sequence of high-level procedures, wherein the trace file is generated such that return parameters supplied from the high-level procedures to the executable instruction stream are documented in the trace file as comments; program instructions for editing the trace file to alter a behavior specified by the trace file to alter the sequence of high-level procedures; and program instructions for, responsive to a subsequent command, executing the trace file as a script to reproduce at least part of the behavior of the executable instruction stream as modified by the editing of the trace file.
12. The computer program product of claim 9 , further comprising program instructions for receiving a sequence of user input commands invoking the high-level procedures via a command interface, wherein the program instructions for controlling the execution of the executable instruction stream are executed in response to the sequence of user input commands, and wherein the program instructions for generating generate a record of the sequence of user input commands that is subsequently repeated by the program instructions for executing controlling the execution of the trace file.