dm365 udev saved.cmdline

大神们，好：

           请教一下下面shell脚本，平台DM365

#!/bin/sh -e

### BEGIN INIT INFO
# Provides: udev
# Required-Start: mountvirtfs
# Required-Stop:# Default-Start: S
# Default-Stop:
# Short-Description: Start udevd, populate /dev and load drivers.
### END INIT INFO

export TZ=/etc/localtime

[ -d /sys/class ] || exit 1
[ -r /proc/mounts ] || exit 1
[ -x /sbin/udevd ] || exit 1
[ -f /etc/default/udev ] && . /etc/default/udev
[ -f /etc/udev/udev.conf ] && . /etc/udev/udev.conf

kill_udevd() {
if [ -x /sbin/pidof ]; then
pid=`/sbin/pidof -x udevd`
[ -n "$pid" ] && kill $pid
fi
}

export ACTION=add
# propagate /dev from /sys
echo "Starting udev"

# mount the tmpfs on /dev, if not already done
LANG=C awk "\$2 == \"/dev\" && \$3 == \"tmpfs\" { exit 1 }" /proc/mounts && {
mount -n -o mode=0755,size=1M,nr_inodes=8192 -t tmpfs none "/dev"
mkdir -m 0755 /dev/pts
mkdir -m 1777 /dev/shm
}

if [ "$DEVCACHE" != "" ]; then
# Invalidate udev cache if the kernel or its bootargs/cmdline have changed
[ -x /bin/uname ] && /bin/uname -mrspv > /tmp/uname || touch /tmp/uname
[ -r /proc/cmdline ] && cat /proc/cmdline > /tmp/cmdline || touch /tmp/cmdline    //这行注释有影响吗？
[ -r /proc/devices ] && cat /proc/devices > /tmp/devices || touch /tmp/devices
[ -r /proc/atags ] && cat /proc/atags > /tmp/atags || touch /tmp/atags
if [ -e $DEVCACHE ] && \
cmp -s /tmp/uname /etc/udev/saved.uname && \
cmp -s /tmp/cmdline /etc/udev/saved.cmdline && \        //这行注释有影响吗？
cmp -s /tmp/devices /etc/udev/saved.devices && \
cmp -s /tmp/atags /etc/udev/saved.atags; then
(cd /; tar xf $DEVCACHE > /dev/null 2>&1)
not_first_boot=1
fi
fi

if [ ! -e "/lib/modules/$(uname -r)"/modules.dep ] ; then
mkdir -p /lib/modules/$(uname -r)
depmod -ae
fi

# make_extra_nodes
kill_udevd > "/dev/null" 2>&1

# trigger the sorted events
echo -e '\000\000\000\000' > /proc/sys/kernel/hotplug
/sbin/udevd -d

/sbin/udevadm control –env STARTUP=1
if [ "$not_first_boot" != "" ];then
/sbin/udevadm trigger –subsystem-nomatch=tty –subsystem-nomatch=mem –subsystem-nomatch=vc –subsystem-nomatch=vtconsole –subsystem-nomatch=misc –subsystem-nomatch=dcon –subsystem-nomatch=pci_bus –subsystem-nomatch=graphics –subsystem-nomatch=backlight –subsystem-nomatch=video4linux –subsystem-nomatch=platform    这几句是什么意思？
(/sbin/udevadm settle –timeout=8; /sbin/udevadm control –env STARTUP=)&
else
/sbin/udevadm trigger
/sbin/udevadm settle
fi

exit 0

请大神赐教，谢谢

Chris Meng：

你好，

udevadm的信息你可以看看下面的链接：

http://www.linux-commands-examples.com/udevadm