lfs-book/udev-lfs/udevd.8

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.TH "SYSTEMD\-UDEVD\&.SERVICE" "8" "" "systemd 202" "udevd"
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.SH "NAME"
udevd \- Device event managing daemon
.SH "SYNOPSIS"
.HP \w'\fB/usr/lib/udevd\fR\ 'u
\fB/lib/udev/udevd\fR [\fB\-\-daemon\fR] [\fB\-\-debug\fR] [\fB\-\-children\-max=\fR] [\fB\-\-exec\-delay=\fR] [\fB\-\-resolve\-names=early|late|never\fR] [\fB\-\-version\fR] [\fB\-\-help\fR]
.SH "DESCRIPTION"
.PP
\fBudevd\fR
listens to kernel uevents\&. For every event, udevd executes matching instructions specified in udev rules\&. See
\fBudev\fR(7)\&.
.PP
The behavior of the running daemon can be changed with
\fBudevadm control\fR\&.
.SH "OPTIONS"
.PP
\fB\-\-daemon\fR
.RS 4
Detach and run in the background\&.
.RE
.PP
\fB\-\-debug\fR
.RS 4
Print debug messages to stderr\&.
.RE
.PP
\fB\-\-children\-max=\fR
.RS 4
Limit the number of events executed in parallel\&.
.RE
.PP
\fB\-\-exec\-delay=\fR
.RS 4
Delay the execution of RUN instruction by the given number of seconds\&. This option might be useful when debugging system crashes during coldplug caused by loading non\-working kernel modules\&.
.RE
.PP
\fB\-\-resolve\-names=\fR
.RS 4
Specify when udevd should resolve names of users and groups\&. When set to
\fBearly\fR
(the default) names will be resolved when the rules are parsed\&. When set to
\fBlate\fR
names will be resolved for every event\&. When set to
\fBnever\fR
names will never be resolved and all devices will be owned by root\&.
.RE
.PP
\fB\-\-version\fR
.RS 4
Print version number\&.
.RE
.PP
\fB\-\-help\fR
.RS 4
Print help text\&.
.RE
.SH "ENVIRONMENT"
.PP
\fI$UDEV_LOG=\fR
.RS 4
Set the logging priority\&.
.RE
.SH "KERNEL COMMAND LINE"
.PP
Parameters starting with "rd\&." will be read when
\fBudevd\fR
is used in an initrd\&.
.PP
\fIudev\&.log\-priority=\fR, \fIrd\&.udev\&.log\-priority=\fR
.RS 4
Set the logging priority\&.
.RE
.PP
\fIudev\&.children\-max=\fR, \fIrd\&.udev\&.children\-max=\fR
.RS 4
Limit the number of events executed in parallel\&.
.RE
.PP
\fIudev\&.exec\-delay=\fR, \fIrd\&.udev\&.exec\-delay=\fR
.RS 4
Delay the execution of RUN instruction by the given number of seconds\&. This option might be useful when debugging system crashes during coldplug caused by loading non\-working kernel modules\&.
.RE
.PP
\fInet\&.ifnames=\fR
.RS 4
Network interfaces are renamed to give them predictable names when possible\&. It is enabled by default, specifying 0 disables it\&.
.RE
.SH "CONFIGURATION FILE"
.PP
udev expects its main configuration file at
/etc/udev/udev\&.conf\&. It consists of a set of variables allowing the user to override default udev values\&. All empty lines or lines beginning with \*(Aq#\*(Aq are ignored\&. The following variables can be set:
.PP
\fIudev_log\fR
.RS 4
The logging priority\&. Valid values are the numerical syslog priorities or their textual representations:
\fBerr\fR,
\fBinfo\fR
and
\fBdebug\fR\&.
.RE
.SH "SEE ALSO"
.PP
\fBudev\fR(7),
\fBudevadm\fR(8)