# d? command

The d? command displays or changes the
default dump string.

## Syntax

```
 d?
```

## Description

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.

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Source: https://d3codex.com/unix/d-questionmark-command/ - part of the D3Codex reference.