• 函数语法案例1
• 一、rsync启停脚本（函数）
• 1) 脚本
• 2) 执行结果：
• 函数语法案例2
• 一、函数传参测试网址异常
• 1. 基本实现
• 1) 代码
• 2) 执行情况
• 2. 改为命令行传参
• 1) 脚本
• 2) 执行结果

函数语法案例1

一、rsync启停脚本（函数）

1) 脚本

• cat /server/scripts/b6.sh

#!/bin/sh
# chkconfig: 2345 20 80
# description:rsyncd start up scripts by noah.
. /etc/init.d/functions
function usage () {
    echo $"usage:$0{start|stop|restart}"
    exit 1
}
function start () {
     rsync --daemon
     sleep 1
     if [ `netstat -lntup|grep rsync|wc -l` -ge 1 ]
       then
         action "rsyncd is started." /bin/true
     else
         action "rsyncd is started." /bin/false
     fi
}
function stop () {
     pkill rsync &>/dev/null
     sleep 2
     if [ `netstat -lntup|grep rsync|wc -l` -eq 0 ]
       then
         action "rsyncd is stopped." /bin/true
     else
         action "rsyncd is stopped." /bin/false
     fi
}
function main () {
  if [ $# -ne 1 ]
    then
      usage
  fi
  if [ "$1" = "start" ]
    then
      start
   elif [ "$1" = "stop" ]
     then
       stop
   elif [ "$1" = "restart" ]
     then
       stop
       sleep 2
       start
   else
       usage
fi
}
main $*

2) 执行结果：

• sh /server/scripts/b6.sh stop
  rsyncd is stopped. [确定]
• sh /server/scripts/b6.sh start
  Failed to parse config file: /etc/rsyncd.conf
  rsyncd is started. [失败]

函数语法案例2

一、函数传参测试网址异常

1. 基本实现

1) 代码

• cat /server/scripts/b5.sh

#!/bin/bash
function usage () {
  echo "usage:$0 input one url"
  exit 1
}
#错误提示函数
function check_url () {
  wget --spider -q -o /dev/null --tries=1 -T 5 $1
  if [ $? -eq 0 ]
    then
      echo "$1 is yes."
  else
      echo "$1 is no."
  fi
}
#url测试函数，注意$1
function main () {
  if [ $# -ne 1 ]
    then
      usage
  fi
  check_url $1
}
#主函数，先判断参数个数，不符合要求调用错误提示函数提示，符合要求的话，调用check_url函数并把$1传递给函数
main $*
#这是将命令行接受到的所有参数，作为函数参数传递给函数内部的一种常用手法

2) 执行情况

• sh /server/scripts/b5.sh www.baidu.com
  www.baidu.com is yes.
• sh /server/scripts/b5.sh www.baidu.co
  www.baidu.co is no.
• sh /server/scripts/b5.sh www.baidu.com abc.com
  usage:/server/scripts/b5.sh input one url

2. 改为命令行传参

1) 脚本

• cat /server/scripts/b5.sh

#!/bin/bash
[ -f /etc/init.d/functions ] && . /etc/init.d/functions || exit 1
function usage () {
  echo "usage:$0 input one url"
  exit 1
}
function check_url () {
  wget --spider -q -o /dev/null --tries=1 -T 5 $1
  if [ $? -eq 0 ]
    then
      action "$1 is yes." /bin/true   
  else
      action "$1 is no." /bin/false
  fi
}
function main () {
  if [ $# -ne 1 ]
    then
      usage
  fi
  check_url $1
}
main $*

2) 执行结果

• sh /server/scripts/b5.sh www.baidu.com
  www.baidu.com is yes. [确定]
• sh /server/scripts/b5.sh www.baidu.co
  www.baidu.co is no. [失败]