chdef Command

Purpose

Changes the default value of the predefined attribute.

Syntax

chdef [-a Attribute = Value -c Class -s Subclass -t Type]

chdef [-H]

chdef [-h]

Description

The chdef command modifies the default value of a predefined attribute of the specified device type. The modified default value must be within a specified list or range of values for the specified attribute, and only attributes, that have an explicit list or range of values can be modified. For devices that are of the same class, subclass, and type that are currently configured using the default value of the attribute, modifying the default value does not take effect for the device until you reboot or a subsequent unconfiguration and configuration operation takes place. This is similar to running the chdev command operation with the -P option except that the chdef command modifies every device of the same class, subclass, and type.

Note: It is recommended but not necessary to run the bosboot command after an execution of the chdef command.

Flags

Item	Description
-a Attribute = Value	Specifies the device attribute-value pair that can be used for setting the new default value. The Attribute=Value variable can be used to specify one attribute=value pair.
-c Class	Specifies the device class.
-h	Displays the command usage message.
-H	Displays headers above the column output.
-s Subclass	Specifies the subclass which is of the device.
-t Type	Specifies the device type from the predefined devices object class.

Security

Access Control

Privilege Control: Only the root user has the execute (x) access to this command.

Auditing Events

Event	Information
DEV_DEFAULT	The command line on the device.

Attention RBAC users and Trusted AIX® users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.

Examples

To change the default value for the hcheck_interval attribute for an scsd disk from 0 to 3, enter:
```
chdef -a hcheck_interval=3 -c disk -s scsi -t scsd
```
To change the default value for the hcheck_interval attribute for an scsd disk back to the default of 0, enter:
```
chdef -a hcheck_interval=0 -c disk -s scsi -t scsd
```
To list all attributes that have modified default values with a header, enter:
```
chdef -H
```

Files

Item	Description
/usr/sbin/chdef	Contains the chdef command.