Linux学习笔记16：shell函数练习

可以组织一些常用的方法，写到函数里面，作为公共的方法方便shell脚本调用，这样可以简化步骤，提高可读性，不用重复造轮子了。

# 调用系统公共函数方法
. /etc/init.d/functions

阶乘

fact(){
				if [ $1 -eq 1 ];then
								echo 1
				else
								echo $[$1*$(fact $[$1-1])]
				fi
}

汉诺塔

#local i=1
hanio(){
								if [ $1 -eq 1 ];then
												echo "第$i步：$2-->$4"
								else

												hanio $[$1-1] $2 $4 $3
												let i+=1
												echo "第$i步：$2-->$4"
												let i+=1
												hanio $[$1-1] $3 $2 $4


								fi
}

判断系统版本

sys_ver(){
				VER=`cat /etc/redhat-release |sed -nr 's/.* ([0-9]+)\..*/\1/p'`
				return $VER

}

获取任意一块网卡的ip地址

get_ip(){
				for nic in $*;do
								#echo ${nic}的IP地址是：`ip addr show $nic 2> /dev/null |sed -nr 's/.* ([0-9.]+).* [0-9.]+ .*$/\1/p'`
								RES=`ip addr show $nic 2> /dev/null|sed -nr 's/.* ([0-9.]+).* [0-9.]+ .*$/\1/p'`
								#echo $RES
								if [ -z "$RES" ];then
												echo ${nic}不存在
								else
												echo ${nic}的IP地址是：`ip addr show $nic |sed -nr 's/.* ([0-9.]+).* [0-9.]+ .*$/\1/p'`
								fi
				done

}

打印绿色OK和红色FAILED

service_status(){

				if [ $# -eq 0 ];then
								echo "Usage: $0 service_name ..."
				else
								for service in $*;do
												RES=`ls /usr/lib/systemd/system |grep $service.service`
												if [ -z "$RES" ];then
																action "$service服务没有安装" false
												else
																action $service的状态：`systemctl status $service |sed -nr '/active/s/[[:space:]]+Active: (\b\w+\b) .*/\1/p'` true
																#STATUS=`systemctl status $service |sed -nr '/active/s/[[:space:]]+Active: (\b\w+\b) .*/\1/p'`
																#echo $STATUS
												fi
								done
				fi
				#return $STATUS
}

start, stop, restart, status --模拟service

start(){
				if [ ! -e /var/lock/subsys/$0 ];then
								touch /var/lock/subsys/$0
								action "启动成功" true
				else
								action "已经处于启动状态，无需处理" true
				fi
}
stop(){
				if [ ! -e /var/lock/subsys/$0 ];then
								action "已经处于停止状态，无需处理" false
				else
								rm -rf /var/lock/subsys/$0
								action "服务停止成功!" true
				fi
}
restart(){
				if [ ! -e /var/lock/subsys/$0 ];then
								touch /var/lock/subsys/$0;action "启动成功" true
				else
								rm -rf /var/lock/subsys/$0;touch /var/lock/subsys/$0;action "重启成功" true
				fi
}
status(){
				if [ ! -e /var/lock/subsys/$0 ];then
								action "服务停止状态" false
				else
								action "服务启动状态" true
				fi
}

#未完待续...