shell语法习题练习进阶版

第4章 shell语法深度习题练习

4.1 使用if,case,函数的方法将服务改成system(centos6)

4.1.1 if方法

4.1.1.1 system实现

4.1.1.1.1 编写代码信息

[root@oldboyedu run]# vim /server/scripts/rsyncd

para=$1

proc_file="/var/run/rsyncd.pid"

if [ "x$para" == "xstart" ]

then

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

sleep 1

rsync --daemon &>/dev/null

else

rsync --daemon &>/dev/null

fi

elif [ "x$para" == "xstop" ]

then

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

else

rsync --daemon &>/dev/null

sleep 1

kill `cat /var/run/rsyncd.pid` &>/dev/null

fi

elif [ "x$para" == "xrestart" ]

then

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

sleep 2

rsync --daemon &>/dev/null

else

rsync --daemon &>/dev/null

fi

else

echo $0 "[stop] [start] [restart]"

fi

4.1.1.1.2 将rsync加入开机自启动里面

[root@oldboyedu run]# mv /server/scripts/rsyncd /etc/init.d/

[root@oldboyedu run]# cd /etc/init.d/

[root@oldboyedu init.d]# chmod +x rsyncd

[root@oldboyedu init.d]#

[root@oldboyedu init.d]# vim rsyncd

#!/bin/bash

# chkconfig: 2345 98 99

para=$1

[root@oldboyedu init.d]# chkconfig --add rsyncd

[root@oldboyedu init.d]#

[root@oldboyedu init.d]# chkconfig --list rsyncd

rsyncd     0:off    1:off    2:on    3:on    4:on    5:on    6:off

[root@oldboyedu init.d]#

4.1.1.1.3 使用service测试

[root@oldboyedu ~]# service rsyncd start

[root@oldboyedu ~]# service rsyncd restart

[root@oldboyedu ~]#

4.1.2 函数和case结合方法

4.1.2.1 编写代码信息

[root@oldboyedu scripts]# cat /server/scripts/rsyncd

#!/bin/bash

# chkconfig: 2345 98 99

proc_file="/var/run/rsyncd.pid"

START() {

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

sleep 1

rsync --daemon &>/dev/null

else

rsync --daemon &>/dev/null

fi

}

STOP() {

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

else

rsync --daemon &>/dev/null

sleep 1

kill `cat /var/run/rsyncd.pid` &>/dev/null

fi

}

RESTART() {

if [ -f $proc_file ]

then

kill `cat /var/run/rsyncd.pid` &>/dev/null

sleep 2

rsync --daemon &>/dev/null

else

rsync --daemon &>/dev/null

fi

}

OTHER() {

echo $0 "[stop] [start] [restart]"

}

case $1 in

start) START ;;

stop) STOP ;;

restart) RESTART ;;

*) OTHER ;;

esac

4.1.2.2 将rsyncd加入开机自启

[root@oldboyedu run]# mv /server/scripts/rsyncd /etc/init.d/

[root@oldboyedu run]# cd /etc/init.d/

[root@oldboyedu init.d]# chmod +x rsyncd

[root@oldboyedu init.d]#

[root@oldboyedu init.d]# vim rsyncd

#!/bin/bash

# chkconfig: 2345 98 99

para=$1

[root@oldboyedu init.d]# chkconfig --add rsyncd

[root@oldboyedu init.d]#

[root@oldboyedu init.d]# chkconfig --list rsyncd

rsyncd     0:off    1:off    2:on    3:on    4:on    5:on    6:off

[root@oldboyedu init.d]#

4.1.2.3 使用service进行测试

[root@oldboyedu scripts]# service rsyncd start

[root@oldboyedu scripts]# service rsyncd stop

[root@oldboyedu scripts]#

4.2 将服务改成systemctl(centos7)

4.2.1 将centos6下面的脚本rsyncd移动到centos7下

scp -r root@10.0.0.222:/etc/init.d/rsyncd /server/

[root@m01 server] # ls

regular rsyncd scripts

mv rsyncd /etc/init.d/

4.2.2 编写centos7的配置文件(man systemctl)

网址: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/system_administrators_guide/index#sect-Managing_Services_with_systemd-Targets

[Unit]

Description= this is a new rsync

After=network.service

[Service]

Type=forking

ExecStart=/bin/sh /etc/init.d/rsyncd start

ExecStop=/bin/sh /etc/init.d/rsyncd stop

ExecReload=/bin/sh /etc/init.d/rsyncd restart

[Install]

WantedBy=multi.user_target

4.2.3 启动rsyncd

[root@m01 system] # systemctl start rsyncd-new.service

[root@m01 system] # systemctl status rsyncd-new.service

● rsyncd-new.service - this is a new rsync

Loaded: loaded (/usr/lib/systemd/system/rsyncd-new.service; disabled; vendor preset: disabled)

Active: active (running) since Wed 2020-01-08 11:59:17 CST; 1s ago

Process: 4374 ExecStart=/bin/sh /etc/init.d/rsyncd start (code=exited, status=0/SUCCESS)

Main PID: 4377 (rsync)

Tasks: 1

CGroup: /system.slice/rsyncd-new.service

└─4377 rsync --daemon

Jan 08 11:59:17 m01 systemd[1]: Starting this is a new rsync...

Jan 08 11:59:17 m01 systemd[1]: Started this is a new rsync.

[root@m01 system] #

4.3 实现1-100的和(while循环和for循环)

[root@m01 test_init] # cat para_0.sh

#!/bin/bash

sum=0

i=0

while [ $i -le 100 ]

do

((sum=sum+i))

let i++

done

echo $sum

[root@m01 test_init] # sh para_0.sh

5050

[root@m01 test_init] #

[root@m01 test_init] # cat para_0.sh

#!/bin/bash

sum=0

i=0

for i in `seq 100`

do

((sum=sum+i))

done

echo $sum

[root@m01 test_init] # sh para_0.sh

5050

[root@m01 test_init] #

4.4 使用for循环判断10.0.0.0网段有多少台机器是通的

[root@m01 test_init] # cat para_0.sh

#!/bin/bash

for i in {1..254}

do

{

ping -c1 -W1 10.0.0.$i &>/dev/null

if [ $? -eq 0 ]

then

echo "10.0.0.$i success"

fi

} &

done

[root@m01 test_init] # sh para_0.sh

10.0.0.1 success

10.0.0.61 success

10.0.0.222 success

10.0.0.254 success

[root@m01 test_init] #

4.5 实现串联执行脚本的时候输出过多的问题

4.5.1 ctrl+z

4.5.1.1 使用ctrl+z让程序进入后台执行

4.5.1.2 查看进入后台的进程

• jobs                查看所有暂停的程序
• bg                在后台运行
• fg                在前台运行

4.5.1.3 结束暂停的程序进程

4.5.2 使用加速来进行处理

4.5.3 使用screen来进行处理

通过命令创建一个shell环境,

4.5.3.1 安装screen

[root@m01 test_init] # yum -y install screen

4.5.3.2 screen常用的参数

screen -ls                    查看当前在screen存在的进程信息

screen -r                    恢复当前在screen存在的进程信息

screen +a +d                相当于断开窗口连接

screen +a +k                相当于在screen窗口中先ctrl+c,接着ctrl+d

4.5.3.3 在screen窗口运行

4.6 nmap的使用方法

4.6.1 nmap的概念介绍

nmap是网络扫描工具,用来扫描网络上面的连接端,(IP/端口,域名)

4.6.2 nmap的使用

nmap -sn 10.0.0.0/24            只做ping,不做端口扫描(n不做反向解析)

nmap 10.0.0.0/24 1-1024            探测10.0.0.0网段1-1024哪些端口开放的