### 2.3 Output files ¶

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.