+
+.SH USAGE WITH UDEV
+If \fBscsi_id\fP is invoked with one argument without a leading \-, it
+assumes it is called for a hotplug event, and looks for the sysfs device
+in the DEVPATH environment variable.
+
+This mode is used when run via the \fBudev\fP PROGRAM key. Passing any
+arguments or options as part of the PROGRAM rule breaks this assumption,
+and the results will likely not be as expected.
+
+When in this mode, all errors and warnings are sent via syslog.
+
+To determine the specific value needed in a RESULT key, use the -s option,
+for example:
+
+.sp
+.nf
+/sbin/scsi_id -s /block/sda
+.fi
+.P
+
+An example \fBudev\fP rule using \fBscsi_id\fP, that will name a block
+device and any partitions for the device matching the \fBscsi_id\fP output
+of 312345:
+
+.sp
+.nf
+BUS="scsi", PROGRAM="/sbin/scsi_id", RESULT="312345", NAME="disk%n"
+.fi
+.P
+