---
name: "devd.conf"
section: "5"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/devd.conf"
---

# devd.conf(5)

configuration file format for devd(8)

## NAME

**devd.conf** – configuration file format for [devd(8)](/devd/8.md)

## DESCRIPTION

### General Syntax

A [devd(8)](/devd/8.md) configuration consists of two general features, statements and comments. All statements end with a semicolon. Many statements can contain substatements, which are also terminated with a semicolon.

The following statements are supported:

- **attach**

  Specifies various matching criteria and actions to perform when a newly attached device matches said criteria.

- **detach**

  Specifies various matching criteria and actions to perform when a newly detached device matches said criteria.

- **nomatch**

  Specifies various matching criteria and actions to perform when no device driver currently loaded in the kernel claims a (new) device.

- **notify**

  Specifies various matching criteria and actions to perform when the kernel sends an event notification to userland.

- **options**

  Specifies various options and parameters for the operation of [devd(8)](/devd/8.md).

Statements may occur in any order in the configuration file, and may be repeated as often as required. Further details on the syntax and meaning of each statement and their substatements are explained below.

Each statement, except **options** has a priority (an arbitrary number) associated with it, where ‘0’ is defined as the lowest priority. If two statements match the same event, only the action of the statement with highest priority will be executed. In this way generic statements can be overridden for devices or notifications that require special attention.

The general syntax of a statement is:

```
statement priority {
	substatement "value";
	...
	substatement "value";
};
```

### Sub-statements

The following sub-statements are supported within the **options** statement.

- **directory** "*/some/path*";

  Adds the given directory to the list of directories from which [devd(8)](/devd/8.md) will read all files named "\*.conf" as further configuration files. Any number of **directory** statements can be used.

- **pid-file** "*/var/run/devd.pid*";

  Specifies PID file.

- **set** *regexp-name* "*(some\|regexp)*";

  Creates a regular expression and assigns it to the variable *regexp-name*. The variable is available throughout the rest of the configuration file. If the string begins with ‘!’, it matches if the regular expression formed by the rest of the string does not match. All regular expressions have an implicit ‘^$’ around them.

The following sub-statements are supported within the **attach** and **detach** statements.

- **action** "*command*";

  Command to execute upon a successful match. Example “/etc/pccard\_ether $device-name start”.

- **class** "*string*";

  This is shorthand for “**match** "class" "*string*"”.

- **device-name** "string";

  This is shorthand for “**match** "device-name" "*string*"”. This matches a device named *string*, which is allowed to be a regular expression or a variable previously created containing a regular expression. The “device-name” variable is available for later use with the **action** statement.

- **match** "*variable*" "*value*";

  Matches the content of *value* against *variable*; the content of *value* may be a regular expression. Not required during **attach** nor **detach** events since the **device-name** statement takes care of all device matching. For a partial list of variables, see below.

- **media-type** "*string*";

  For network devices, **media-type** will match devices that have the given media type. Valid media types are: “Ethernet”, “802.11”, and “ATM”.

- **subdevice** "*string*";

  This is shorthand for “**match** "subdevice" "*string*"”.

The following sub-statements are supported within the **nomatch** statement.

- **action** "*command*";

  Same as above.

- **match** "*variable*" "*value*";

  Matches the content of *value* against *variable*; the content of *value* may be a regular expression. For a partial list of variables, see below.

The following sub-statements are supported within the **notify** statement. The “notify” variable is available inside this statement and contains, a value, depending on which system and subsystem that delivered the event.

- **action** "*command*";

  Command to execute upon a successful match. Example “/etc/rc.d/power\_profile $notify”.

- **match** "*system* \| *subsystem* \| *type* \| *notify*" "*value*";

  Any number of **match** statements can exist within a **notify** statement; *value* can be either a fixed string or a regular expression. Below is a list of available systems, subsystems, and types.

- **media-type** "*string*";

  See above.

### Variables that can be used with the match statement

A partial list of variables and their possible values that can be used together with the **match** statement. The variables are published by the bus based on characteristics of the device that generated the event (for device events). Variables for other classes of events are dependent on those events.

- **Variable**

  **Description**

- \*

  The entire message from the current event.

- \_

  The entire message from the current event, after the initial type character.

- timestamp

  The time this event was processed, in seconds since 1970 dot fraction.

- bus

  Device name of parent bus.

- cdev

  Device node path if one is created by the [devfs(4)](/devfs/4.md) filesystem.

- class

  Device class.

- comm

  Executable name (kernel).

- core

  Path to core file (kernel).

- device

  Device ID.

- devclass

  Device Class (USB).

- devsubclass

  Device Sub-class (USB).

- device-name

  Name of attached/detached device.

- endpoints

  Endpoint count (USB).

- function

  Card functions.

- interface

  Interface ID (USB).

- intclass

  Interface Class (USB).

- intprotocol

  Interface Protocol (USB).

- intsubclass

  Interface Sub-class (USB).

- jail

  Jail name for the process triggering the rule (RCTL).

- mode

  Peripheral mode (USB).

- notify

  Match the value of the “notify” variable.

- parent

  Parent device.

- pid

  PID of the process triggering the rule (RCTL).

- port

  Hub port number (USB).

- product

  Product ID (USB).

- release

  Hardware revision (USB).

- ruid

  Real UID of the process triggering the rule (RCTL).

- rule

  Rule (RCTL).

- sernum

  Serial Number (USB).

- slot

  Card slot.

- subvendor

  Sub-vendor ID (PCI).

- subdevice

  Sub-device ID (PCI).

- subsystem

  Matches a subsystem of a system, see below.

- system

  Matches a system type, see below.

- type

  Type of notification, see below.

- vendor

  Vendor ID.

### Notify matching

A partial list of systems, subsystems, and types used within the **notify** mechanism.

| | | | |
| --- | --- | --- | --- |
| ACPI |  |  |  |
| ACPI | ACAD |  |  |
| ACPI | Button |  |  |
| ACPI | CMBAT |  |  |
| ACPI | Dock |  |  |
| ACPI | Lid |  |  |
| ACPI | PROCESSOR |  |  |
| ACPI | Resume |  |  |
| ACPI | Suspend |  |  |
| ACPI | Thermal |  |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| AEON | power | press |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| CAM |  |  |  |
| CAM | periph |  |  |
| CAM | periph | error |  |
| CAM | periph | invalidate |  |
| CAM | periph | timeout |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| CARP |  |  |  |
| CARP | *vhid@inet* |  |  |
| CARP | *vhid@inet* | MASTER |  |
| CARP | *vhid@inet* | BACKUP |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| coretemp |  |  |  |
| coretemp | Thermal |  |  |
| coretemp | Thermal | temperature |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| DEVFS |
| DEVFS | CDEV | CREATE |  |
| DEVFS | CDEV | DESTROY |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| ETHERNET | *inet* | IFATTACH |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| GEOM |  |  |  |
| GEOM | DEV | CREATE |  |
| GEOM | DEV | DESTROY |  |
| GEOM | DEV | GEOM::physpath |  |
| GEOM | DEV | GEOM::rotation\_rate |  |
| GEOM | DEV | MEDIACHANGE |  |
| GEOM | DEV | SIZECHANGE |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| IFNET |
| IFNET | *inet* |  |  |
| IFNET | *inet* | LINK\_UP |  |
| IFNET | *inet* | LINK\_DOWN |  |
| IFNET | *inet* | ATTACH |  |
| IFNET | *inet* | DETACH |  |
| IFNET | *inet* | RENAME |  |
| IFNET | *inet* | ADDR\_ADD |  |
| IFNET | *inet* | ADDR\_DEL |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| kernel | signal | coredump |  |
| kernel | power | resume |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| nvme | controller |  |  |
| nvme | controller | SMART\_ERROR |  |
| nvme | controller | RESET |  |
| nvme | controller | RECONNECT |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| PMU |  |  |  |
| PMU | AC |  |  |
| PMU | AC | overvoltage |  |
| PMU | AC | plugged |  |
| PMU | AC | unplugged |  |
| PMU | Battery |  |  |
| PMU | Battery | absent |  |
| PMU | Battery | charged |  |
| PMU | Battery | charging |  |
| PMU | Battery | disconnected |  |
| PMU | Battery | high-temp |  |
| PMU | Battery | low-temp |  |
| PMU | Battery | plugged |  |
| PMU | Battery | shutdown-threshold |  |
| PMU | Battery | warning-threshold |  |
| PMU | Button | pressed |  |
| PMU | keys |  |  |
| PMU | keys | brightness |  |
| PMU | keys | mute |  |
| PMU | keys | volume |  |
| PMU | keys | eject |  |
| PMU | lid | close |  |
| PMU | lid | open |  |
| PMU | POWER | ACLINE |  |
| PMU | USB | overvoltage |  |
| PMU | USB | plugged |  |
| PMU | USB | undervoltage |  |
| PMU | USB | unplugged |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| RCTL |  |  |  |
| RCTL | rule | matched |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| USB |  |  |  |
| USB | DEVICE | ATTACH |  |
| USB | DEVICE | DETACH |  |
| USB | INTERFACE | ATTACH |  |
| USB | INTERFACE | DETACH |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| VFS |  |  |  |
| VFS | FS |  |  |
| VFS | FS | MOUNT |  |
| VFS | FS | REMOUNT |  |
| VFS | FS | UNMOUNT |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| VT | BELL | RING |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| ZFS | ZFS |  |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

| | | | |
| --- | --- | --- | --- |
| SND |  |  |  |
| SND | CONN | IN |  |
| SND | CONN | OUT |  |
| SND | CONN | NODEV |  |

**System** 	 **Subsystem** 	 **Type** 	 **Description**

A link state change to UP on the interface “fxp0” would result in the following notify event:

```
system=IFNET subsystem=fxp0 type=LINK_UP
```

An AC line state change to “offline” would result in the following event:

```
system=ACPI subsystem=ACAD notify=0x00
```

### Comments

Comments may appear anywhere that whitespace may appear in a configuration file. To appeal to programmers of all kinds, they can be written in C, C++, or shell/Perl constructs.

C-style comments start with the two characters ‘/\*’ (slash, star) and end with ‘\*/’ (star, slash). Because they are completely delimited with these characters, they can be used to comment only a portion of a line or to span multiple lines.

C-style comments cannot be nested. For example, the following is not valid because the entire comment ends with the first ‘\*/’:

```
/* This is the start of a comment.
   This is still part of the comment.
/* This is an incorrect attempt at nesting a comment. */
   This is no longer in any comment. */
```

C++-style comments start with the two characters ‘//’ (slash, slash) and continue to the end of the physical line. They cannot be continued across multiple physical lines; to have one logical comment span multiple lines, each line must use the ‘//’ pair. For example:

```
// This is the start of a comment.  The next line
// is a new comment, even though it is logically
// part of the previous comment.
```

### Notes on Variable Expansion

Variables are expanded by preceding them by a “$” sign. Any text immediately following that sign, starting with a letter, a minus sign “-”, an underscore “\_”, or an asterisk “\*” is considered an internal variable, and expanded accordingly. If that variable does not exist, it silently expands to an empty string. Consequently, if the intention is to pass a [sh(1)](/sh/1.md) variable, it must be surrounded by braces to prevent it from being considered an internal variable.

See EXAMPLES for a detailed example.

To prevent issues with special shell characters, the following happens for each variable **$foo**.

1. The characters “$'” are inserted.

2. The string “$foo” is removed.

3. The value of the **foo** variable is inserted into the buffer with all single quote characters prefixed by a backslash.

4. A final “'” is inserted.

See [sh(1)](/sh/1.md) for what this construct means. It is safe in all context, except one: inside single quotes. If foo=meta and bar=var, then a rule like the following:

```
action "echo '$foo $bar'";
```

will be presented to the shell via [system(3)](/system/3.md) as

```
echo '$'meta' $'var''
```

which produces the following output:

```
$meta $var
```

as its output. This is an unanticipated result. A future version of this software will change this behavior. Users are discouraged from using single quotes inside **action** value without due care.

The above should be written as

```
action "echo $foo' '$bar"
```

to produce a single argument to echo. Given the above expansion, juxtaposing bare variables with single quote expressions will produce the right output, regardless of the value of the variable.

## FILES

- */etc/devd.conf*

  The [devd(8)](/devd/8.md) configuration file.

- */etc/devd*

  A directory that **devd** searches for additional configuration files.

- */usr/local/etc/devd*

  A directory that **devd** searches for additional configuration files.

## EXAMPLES

```
#
# This will catch link down events on the interfaces fxp0 and ath0
#
notify 0 {
	match "system"			"IFNET";
	match "subsystem"		"(fxp0|ath0)";
	match "type"			"LINK_DOWN";
	action "logger $subsystem is DOWN";
};
#
# Match lid open/close events
# These can be combined to a single event, by passing the
# value of $notify to the external script.
#
notify 0 {
	match "system"			"ACPI";
	match "subsystem"		"Lid";
	match "notify"			"0x00";
	action "logger Lid closed, we can sleep now!";
};
notify 0 {
	match "system"			"ACPI";
	match "subsystem"		"Lid";
	match "notify"			"0x01";
	action "logger Lid opened, the sleeper must awaken!";
};
#
# Match a USB device type
#
notify 0 {
	match "system"			"USB";
	match "subsystem"		"INTERFACE";
	match "type"			"ATTACH";
	match "intclass"		"0x0e";
	action "logger USB video device attached";
};
#
# Try to configure ath and iwn devices with pccard_ether
# as they are attached.
#
attach 0 {
        device-name "(ath|iwn)[0-9]+";
        action "/etc/pccard_ether $device-name start";
};
#
# Stop ath and iwn devices as they are detached from
# the system.
#
detach 0 {
        device-name "(ath|iwn)[0-9]+";
        action "/etc/pccard_ether $device-name stop";
};
```

The following example illustrates the difference between internal and shell variables:

```
attach 20 {
        device-name             "umodem[0-9]+";
        match "vendor"          "0x2047";
        match "product"         "0x001(0|3|4)";
        match "interface"       "0";
        action "cd /dev; p=$product; dn=$device-name; \
                un=$(sysctl -n dev.umodem.${dn#umodem}.ttyname); \
                chmod 666 cua${un}; ln -sf cua${un} mspfet${p#0x}";
};
```

“product”, and “device-name” are internal variables. Their contents are initially assigned to shell variables “p”, and “dn”, respectively. Then, variable “dn” is used inside a shell command substitution, assigning to shell variable “un”. Finally, this shell variable is used in two other shell statements, where it needs to be wrapped in braces in order to prevent it from being considered in internal variable to **devd**.

The installed */etc/devd.conf* has many additional examples.

## SEE ALSO

[cam(4)](/cam/4.md), [coretemp(4)](/coretemp/4.md), [devfs(4)](/devfs/4.md), [re\_format(7)](/re_format/7.md), [devd(8)](/devd/8.md)

## BUGS

The variable expansion's interaction with single quotes is suboptimal and surprising.