向自己道歉，没能抽出更多的时间，进度如此的慢。

现在想认真学习下scull模块的这个初始化脚本 scull_init.sh

#!/bin/bash
# Sample init script for the a driver module <rubini@linux.it>DEVICE="scull"
SECTION="misc"# The list of filenames and minor numbers: $PREFIX is prefixed to all names
PREFIX="scull"
FILES="     0 0         1 1         2 2        3 3    priv 16 pipe0 32    pipe1 33    pipe2 34   pipe3 35single 48      uid 64     wuid 80"INSMOD=/sbin/insmod; # use /sbin/modprobe if you preferfunction device_specific_post_load () {true; # fill at will
}
function device_specific_pre_unload () {true; # fill at will
}# Everything below this line should work unchanged for any char device.
# Obviously, however, no options on the command line: either in
# /etc/${DEVICE}.conf or /etc/modules.conf (if modprobe is used)# Optional configuration file: format is
#    owner  <ownername>
#    group  <groupname>
#    mode   <modename>
#    options <insmod options>
CFG=/etc/${DEVICE}.conf# kernel version, used to look for modules
KERNEL=`uname -r`#FIXME: it looks like there is no misc section. Where should it be?
MODDIR="/lib/modules/${KERNEL}/kernel/drivers/${SECTION}"
if [ ! -d $MODDIR ]; then MODDIR="/lib/modules/${KERNEL}/${SECTION}"; fi
#专有命令[ (左中括号, 特殊字符). 这个命令与test命令等价, 并且出于效率上的考虑, 这是一个内建命令
# -d FILE  FILE exists and is a directory# Root or die
if [ "$(id -u)" != "0" ]
thenecho "You must be root to load or unload kernel modules"exit 1
fi# Read configuration file
if [ -r $CFG ]; then
# -r FILE   FILE exists and read permission is granted
#看到这儿了，

    OWNER=`awk "\\$1==\"owner\" {print \\$2}" $CFG`
#读取文件$CFG 若第一个域为owner，则打印第二个域，并赋值到变量OWNER

#但是这条指令在shell里未能正常运行，改为如下：类似的样子

# awk '$1=="DEVICE" {print $2}' scull.init

    GROUP=`awk "\\$1==\"group\" {print \\$2}" $CFG`MODE=`awk "\\$1==\"mode\" {print \\$2}" $CFG`# The options string may include extra blanks or only blanksOPTIONS=`sed -n '/^options / s/options //p' $CFG`
#打印包含options的行

fi# Create device files
function create_files () {cd /devlocal devlist=""

    local file
#如果变量用local来声明，那么它只能在该变量声明的代码块(block of code)中可见

    while true; doif [ $# -lt 2 ]; then break; fi
#$# Number of command-line arguments  or positional parameters   -lt  小于

   file="${DEVICE}$1"mknod $file c $MAJOR $2devlist="$devlist $file"shift 2
#The shift command reassigns the positional parameters, in effect shifting them to the left one notch

    doneif [ -n "$OWNER" ]; then chown $OWNER $devlist; fiif [ -n "$GROUP" ]; then chgrp $GROUP $devlist; fiif [ -n "$MODE"  ]; then chmod $MODE  $devlist; fi
#  -n STRING the length of STRING is nonzero

}# Remove device files
function remove_files () {cd /devlocal devlist=""local filewhile true; doif [ $# -lt 2 ]; then break; fifile="${DEVICE}$1"devlist="$devlist $file"shift 2donerm -f $devlist
}# Load and create files
function load_device () {if [ -f $MODDIR/$DEVICE.o ]; then
#-f  FILE exists and is a regular file

 devpath=$MODDIR/$DEVICE.oelse if [ -f ./$DEVICE.o ]; thendevpath=./$DEVICE.oelsedevpath=$DEVICE; # let insmod/modprobe guessfi; fiif [ "$devpath" != "$DEVICE" ]; thenecho -n " (loading file $devpath)"fiif $INSMOD $devpath $OPTIONS; thenMAJOR=`awk "\\$2==\"$DEVICE\" {print \\$1}" /proc/devices`remove_files $FILEScreate_files $FILESdevice_specific_post_loadelseecho " FAILED!"fi
}# Unload and remove files
function unload_device () {device_specific_pre_unload /sbin/rmmod $DEVICEremove_files $FILES
}case "$1" instart)echo -n "Loading $DEVICE"load_deviceecho ".";;stop)echo -n "Unloading $DEVICE"unload_deviceecho ".";;force-reload|restart)echo -n "Reloading $DEVICE"unload_deviceload_deviceecho ".";;*)echo "Usage: $0 {start|stop|restart|force-reload}"exit 1
esacexit 0