Linux系统启动流程及脚本编程(3)
1.特殊变量值
${变量参数#*字符} 意思是从左至右，以“字符”为分隔符，取第一个分隔符后面的所有字符串
${变量参数##*字符} 意思是从左至右，以“字符”为分隔符，取最后一个分隔符后面的所有字符串
${变量参数%字符*} 意思是从右至左，以“字符”为分隔符，取第一个分隔符后面的所有字符串
${变量参数%%字符*} 意思是从右至左，以“字符”为分隔符，取最后一个分隔符后面的所有字符串
${#变量名} 意思是计算变量里的字符串个数值
例如：假设变量A=“10 23 45 56”，以空白为分隔符，取出以下不同值
2.linux系统时脚本调用基本顺序如下：
2.1:init主进程，读取/etc/inittab配置文件
2.2.从/etc/inittab配置文件中，设定默认运行别级
2.3.从/etc/inittab配置文件中，执行/etc/rc.d/rc.sysinit脚本文件
2.4.从/etc/inittab配置文件中，执行指定运行级别的脚本
如：/etc/rc.d/rc ->/etc/rc.d/rc[0-6].d/*->/etc/rc.d/init.d/*,层层按序调用
2.5.最后执行/etc/rc.d/rc.local脚本
3.订制一个外部命令，如，ls,useradd,mount等命令，而每个命令依赖自己的库文件，
写一个如下脚本，实现自动copy现有系统中的外部命令并且copy对应的库文件
#!/bin/bash
DEST=/mnt/sysroot
libcp() {
LIBPATH=${1%/*}
[ ! -d $DEST$LIBPATH ] && mkdir -p $DEST$LIBPATH
[ ! -e $DEST${1} ] && cp $1 $DEST$LIBPATH && echo "$1 is coped successfully "
}
bincp() {
CMDPATH=${1%/*}
[ ! -d $DEST$CMDPATH ] && mkdir -p $DEST$CMDPATH
[ ! -e $DEST${1} ] && cp $1 $DEST$CMDPATH
for LIB in `ldd $1 | grep -o "/.*lib\(64\)\{0,1\}/[^[:space:]]\{1,\}"`; do
libcp $LIB
done
}
read -p "Please Input You need add command: " CMD
until [ $CMD == ‘q‘ ]; do
if ! which $CMD &> /dev/null; then
ehco "Your command is not exist..."
read -p "Please Input You need add command,again: " CMD
continue
fi
COMMAND=`which $CMD | grep -v "^alias" | grep -o "[^[:space:]]\{1,\}"`
bincp $COMMAND
echo "$COMMAND is copied ok"
read -p "Please Input You need add command: " CMD
done
4.订制一个开关机脚本,名称:/etc/rc.d/init.d/halt
#!/bin/bash
case $0 in
*reboot)
COMMAND=‘/sbin/reboot‘ ;;
*halt)
COMMAND=‘/sbin/halt -p‘ ;;
*)
echo "Only call by *halt | *reboot "
;;
esac
case $1 in
start)
;;
stop)
;;
*)
echo"Usage: `basename $0` {start|stop}"
;;
esac
exec $COMMAND
~
5.订制一个在系统开关机或服务开关时显示OK为绿色，Failed为红色脚本
脚本名称：/etc/rc.d/init.d/functions
#!/bin/bash
SCREEN=`stty -F /dev/console size 2> /dev/null`
COLUMNS=${SCREEN#* }
[ -z $COLUMNS ] && COLUMNS=80
SPA_COL=$[$COLUMNS-14]
RED=‘\033[31m‘
GREEN=‘\033[32m‘
YELLOW=‘\033[33m‘
BLUE=‘\033[34m‘
NORMAL=‘\033[0m‘
success() {
string=$1
RT_COL=$[$SPA_COL-${#string}]
echo -n "$string"
for I in `seq 1 $RT_COL`; do
echo -n " "
done
echo -e "[ ${GREEN}OK${NORMAL} ]"
}
failure() {
string=$1
RT_COL=$[$SPA_COL-${#string}]
echo -n "$string"
for I in `seq 1 $RT_COL`; do
echo -n " "
done
echo -e "[ ${RED}FAILED${NORMAL} ]"
}
~
注意：此脚本也可以设成一个配置文件供其他脚本调用使用
6.订制一个网络启动脚本,名称:/etc/rc.d/init.d/network
#!/bin/bash
# chkconfig: 35 10 89
# description: netwrok service
prog=network
. /etc/rc.d/init.d/functions 调用上面显示服务颜色脚本文件(注意调用时将第一行删除)
CONF=/etc/sysconfig/network-scripts/ifcfg-eth0
. $CONF
start() {
ifconfig eth0 $IPADDR/$NETMASK up
[ -z $GATEWAY ] && route add default gw $GATEWAY
}
stop() {
ifconfig eth0 down
}
status() {
ifconfig eth0
}
usage() {
echo "Usage:$prog: {start|stop|restart|status}"
}
case $1 in
start)
start
success "Config network eth0"
;;
stop)
stop
success "Stop network eth0"
;;
restart)
stop
start
success "Restart network eth0"
;;
status)
status
;;
*)
usage
exit 5
;;
esac
7.订制一个系统初始化脚本/etc/rc.d/rc.sysinit
root@localhost sysroot]# vim etc/rc.d/rc.sysinit
#!/bin/bash
. etc/rc.d/init.d/functions
echo -e "\t Welcome to \033[31mWillow person\033[0m Linux..."
echo "Remount rootfs..."
mount -n -o remount,rw /
mount -a
[ $? -eq 0 ] && success "mount other system files" || failure "mount other system files"
echo "set the hostname..."
#[ -f /etc/sysconfig/network ] && source /etc/sysconfig/network
[ -f /etc/sysconfig/network ] && . /etc/sysconfig/network
[ -z $HOSTNAME -o $HOSTNAME == ‘(none)‘ ] && HOSTNAME=localhost
/bin/hostname $HOSTNAME
insmod /lib/modules/mii.ko
[ $? -eq 0 ] && success "Loading modules mii " || failure "Loading modules mii"
insmod /lib/modules/pcnet32.ko
[ $? -eq 0 ] && success "Loading modules pcnet32 " || failure "Loading modules pcnet32"
#ifconfig eth0 1.1.1.100
ifconfig lo 127.0.0.1
#/bin/bash
/sbin/sysctl -p
7.订制一个基本服务脚本：名称:/etc/rc.d/init.d/Xserver
#!/bin/bash
# chkconfig: 35 68 31
# description: tserve script service
. /etc/rc.d/init.d/functions
#prog=`basename $0`
prog=tserver
lockfile=/var/lock/subsys/$prog
start() {
# echo "Starting $prog..."
touch $lockfile
[ $? -eq 0 ] && success "Starting $prog" || failure " Starting $prog"
}
stop() {
# echo "Stopping $prog..."
[ $? -eq 0 ] && success "Stopping $prog" || failure " Stopping $prog"
rm -rf $lockfile
}
status() {
if [ -f $lockfile ]; then
echo "$prog is Running..."
else
echo "$prog is Stopped..."
fi
}
usage() {
echo "Usage: $prog {start|stop|status|restart}"
}
case $1 in
start)
start ;;
stop)
stop ;;
restart)
stop
start
;;
status)
status
;;
*)
usage
exit 6
;;
esac
本文出自 “夏维柳” 博客，请务必保留此出处http://willow.blog.51cto.com/6574604/1769355
原文地址：http://willow.blog.51cto.com/6574604/1769355
