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DEVD(8)                 FreeBSD System Manager's Manual                DEVD(8)

     devd - Device state change daemon

     devd [-d]

     The devd daemon provides a way to have userland programs run when certain
     kernel events happen.

     The following options are accepted.

     -d      Enable debugging messages and run in the foreground instead of
             becoming a daemon.

     devd is a system daemon that runs in the background all the time.
     Whenever a device is added to or removed from the device tree, devd will
     execute actions specified in devd.conf(5).  For example, devd might
     execute dhclient(8) when an ethernet adapter is added to the system and
     kill the dhclient(8) instance when the same adapter is removed.  Another
     example would be for devd to use a table to locate and load via
     kldload(8) the proper driver for an unrecognized device that is added to
     the system.

     devd hooks into the devctl(4) device driver.  This device driver has
     hooks into the device configuration system.  When nodes are added or
     deleted from the tree, this device will deliver information about the
     event to devd.  Once devd has parsed the message, it will search its
     action list for that kind of event and perform the action with the
     highest matching value.  For most mundane uses, the default handlers are
     adequate.  However, for more advanced users, the power is present to
     tweak every aspect of what happens.

     devd reads /etc/devd.conf and uses that file to drive the rest of the
     process.  While the format of this file is described in devd.conf(5) some
     basics are covered here.  In the options section, one can define multiple
     directories to search for config files.  All files in each of these
     directories are parsed.  These files are intended to be installed by
     third party vendors that wish to hook into the devd system without
     modifying the user's other config files.

     devctl(4), devd.conf(5)

     M. Warner Losh

     devd currently always runs "/etc/devd-generic $device $startstop" for all
     device events, regardless of what the config file says to do.

FreeBSD 11.0-PRERELEASE        October 17, 2002        FreeBSD 11.0-PRERELEASE


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