DejaGnu always writes two kinds of output files. Summary output is
written to the .sum file, and detailed output is written to the
.log file. The tool name determines the prefix for these
files. For example, after running with
--tool gdb, the output
files will be called gdb.sum and gdb.log. For
troubleshooting, a debug log file that logs the operation of Expect is
available. Each of these will be described in turn.