[笔记] /etc/init.d/ 下脚本的通用结构

http://sunxiaqw.blog.163.com/blog/static/99065438201111715813443/

下面以 named 为例 ：

#!/bin/bash

#

# named           This shell script takes care of starting and stopping        # 注释 ：给出脚本的作用

#                 named (BIND DNS server).

#

# chkconfig: - 55 45                                                                               # 注释 ：给出 named 的启动/关闭级别 ，例如

/etc/rc3.d/S55named -> ../init.d/named

/etc/rc6.d/K45named -> ../init.d/named

chkconfig: 345 85 15 （这个比较有意思，345代表在设置在那个level中是on的，如果一个都不想on，那就写一个横线"-"，比如：chkconfig: - 85 15。后面两个数字当然代表S和K的默认排序号啦）
# description: Apache is a World Wide Web server.  It is used to serve \ 
#              HTML files and CGI. 
# processname: httpd 
# pidfile: /var/run/httpd.pid 
# config: /usr/local/apache2/conf/httpd.conf (我装东西比较喜欢都放在/usr/local下)

# Source function library.
. /etc/rc.d/init.d/functions

if [ -f /etc/sysconfig/httpd ]; then
       . /etc/sysconfig/httpd
fi

INITLOG_ARGS=""

apachectl=/usr/local/apache2/bin/apachectl
httpd=${HTTPD-/usr/local/apache2/bin/httpd}

prog="httpd"

start()
{
    ps -ef | grep "$prog" | grep -v "grep" | grep -v "start" > /dev/Null
    if [ "$?" -eq "1" ]; then
        echo -n $"Starting $prog: "
        daemon $httpd $OPTIONS
        ret=$?
        echo
        [ "$ret" -eq "0" ] && touch /var/lock/subsys/httpd
        return 0
    else
        echo "httpd running"
        return 0
    fi
}

stop()

{
    status httpd >/dev/Null >&1
    ret_status=$?
    if [ $ret_status -eq 2 ]; then
        rm -f /var/lock/subsys/httpd /var/run/httpd.pid
        echo "httpd stopped"
        return 0
    elif [ $ret_status -eq 3 ]; then
        echo "httpd stopped"
        return 0
    fi
    echo -n $"Stopping $prog: "
    killproc $httpd
    ret=$?
    echo
    [ "$ret" -eq "0" ] && rm -f /var/lock/subsys/httpd /var/run/httpd.pid
    return 0
}

case "$1" in
    start)
       start
       ;;
    stop)
       stop
       ;;
    status)
       status httpd
       ;;
http://msnpiki.msnfanatic.com/index.php/Main_Page-->

详细出处参考：http://www.itqun.net/content-detail/194818.html

# description: named (BIND) is a Domain Name Server (DNS) \                  # 注释 ；描述所启动的服务的作用

# that is used to resolve host names to IP addresses.

# probe: true

# Source function library.                                                                         # 注释 ：这个也是固定的，functions 脚本提供了公用的函数

. /etc/rc.d/init.d/functions

# Source networking configuration.                                                            # 注释 ：这个也比较常用，用于获得网络的一些基本信息

[ -r /etc/sysconfig/network ] && . /etc/sysconfig/network

RETVAL=0                                                                                             # 注释 ：

prog="named"                                                                                        # 注释 ：

# Check that networking is up.                                                                 # 注释 ：检查网络是否已经启动

[ "${NETWORKING}" = "no" ] && exit 1                                                       # 注释 ：NETWORKING 变量来自于 /etc/sysconfig/network文件

如果等于 no 则退出，返回 1

[ -r /etc/sysconfig/named ] && . /etc/sysconfig/named                                 # 注释 ：如果存在 /etc/sysconfig/named 且可读，则执行它

该文件保存了 named 启动的选项

[ -x /usr/sbin/named ] || exit 1                                                                 # 注释 ：如果存在 /usr/sbin/named 且继续，否则退出，返回1

[ -r ${ROOTDIR}/etc/named.conf ] || exit 1                                                # 注释 ：如果存在 $ROOTDIR/etc/named.conf 且可读，则继续，否则

返回1。ROOTDIR 变量来自于 /etc/sysconfig/named文件

下面是最重要的函数定义，有 start（）、stop（）、status（）、reload（）、restart（）probe（）

下面是 case 语句 ,就是 start、stop、reload、restart 这些了