---
name: "ioreg"
section: "8"
platform: "macos"
package: "IOKitTools"
version: "125"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/ioreg"
---

# ioreg(8)

show I/O Kit registry

## NAME

**ioreg** – show I/O Kit registry

## SYNOPSIS

**ioreg** \[**-abfilrtxy**\] \[**-c** *class*\] \[**-d** *depth*\] \[**-k** *key*\] \[**-n** *name*\] \[**-p** *plane*\] \[**-w** *width*\]

## DESCRIPTION

**ioreg** displays the I/O Kit registry.  It shows the hierarchical registry structure as an inverted tree.  The provider-client relationships among those objects is shown as follows:

\+-o provider\
   \|\
   \+-o client

By default, object properties are not shown.  The use of the **-c**, **-k**, **-l**, or **-n** options cause **ioreg** to show properties for objects that match the specified criteria.

By supplying the **-r** option, the user may specify the object which will appear at the root of the tree with the **-c**, **-k**, or **-n** options.  If root matches more than one object, multiple trees will be displayed.

The options are as follows:

- **-a**

  Archive the output in XML.

- **-b**

  Show the object name in bold.

- **-c**

  Show the object properties only if the object is an instance of, or derives from, the specified C++ *class* (e.g. IOService).

- **-d**

  Limit tree traversal to the specified *depth*. The depth limit is applied with respect to each subtree root individually.  Therefore, supplying a depth of 1 will cause **ioreg** to display only (sub)tree root nodes; children will not be shown.

- **-f**

  Enable smart formatting. **ioreg** knows how to format certain properties so that the output is more readable and meaningful, decoding data fields where appropriate.  Currently supported are \`reg', \`assigned-addresses', \`slot-names', \`ranges', \`interrupt-map', \`interrupt-parent\`, and \`interrupts'.

- **-i**

  Show the object inheritance.

- **-k**

  Show the object properties only if the object has the specified *key*. Substrings do not match; the specified key must be a full property name.

- **-l**

  Show properties for all displayed objects.

- **-n**

  Show the object properties only if the object has the specified *name*. The object location, if any, is considered part of the name, thus pci@f0000000 and pci@f4000000 are distinct names.

- **-p**

  Traverse the registry over the specified *plane*. The default plane value is \`\`IOService''.  The other planes, such as \`\`IODeviceTree'', can be found under the \`\`IORegistryPlanes'' property of the root object (ioreg -d 1 -k IORegistryPlanes).

- **-r**

  Show subtrees rooted by objects that match the specified criteria.  If none of **-c**, **-k**, or **-n** are supplied, **-r** has no effect.

- **-t**

  Show tree location of each subtree.  This option causes **ioreg** to display all nodes between the I/O Kit Root and the root of the displayed subtree, i.e. the subtree's parent, grandparent, etc.

- **-w**

  Clip the output to the specified line *width*. The default width value is the current screen size.  A value of 0 specifies an unlimited line width.

- **-x**

  Show data and numbers as hexadecimal.

**-y** Do not consider DriverKit classes with -c.