The d? command displays or changes the default dump string.
d?
In case of system abort (for example, bus errors, segmentation violations, and so on), the system automatically dumps any critical elements in the file /usr/tmp/ap.core.
The file can be examined with the apcrash command. After the display, the string can be changed by typing the new dump string after the equal sign. The dump string can have up to 15 characters, one-character codes and arguments. For the description of each code, see d command below. The dump string can be different for each process.