shell学习二十二--case语句

「爱情、让人受尽委屈。」 2022-06-05 07:06 288阅读 0赞

一、case结构条件句语法  
case语句适用于需要进行多重分支的应用情况。  
        case分支语句的格式如下：  
            case $变量名 in  
                模式1）命令序列1  
            ;;  
                模式2）命令序列2  
            ;;  
                \*）默认执行的命令序列       
            ;;  
            esac   
  
二、颜色的使用  
让echo输出带颜色的方法有两种  
1.在shell脚本中定义颜色变量，使用echo -e调用变量  
2.定义变量的时候，把echo -e定义到变量中，然后输出变量  
可以让echo输出显示颜色的shell脚本  
\#!/bin/bash  
\#定义颜色的变量  
RED\_COLOR='\\E\[1;31m'    
GREEN\_COLOR='\\E\[1;32m'   
YELOW\_COLOR='\\E\[1;33m'   
BLUE\_COLOR='\\E\[1;34m'    
PINK='\\E\[1;35m'        
RES='\\E\[0m'  
\#需要使用echo -e  
echo -e  "$\{RED\_COLOR\}======red color======$\{RES\}"  
echo -e  "$\{YELOW\_COLOR\}======yelow color======$\{RES\}"  
echo -e  "$\{BLUE\_COLOR\}======green color======$\{RES\}"  
echo -e  "$\{GREEN\_COLOR\}======green color======$\{RES\}"  
echo -e  "$\{PINK\}======pink color======$\{RES\}"  
echo "\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#"  
\#直接把echo -e放到变量里面，使用的时候直接输出变量即可  
SET COLOR\_SUCCESS="echo -en \\\\033\[1;32m"  
SET COLOR\_FAILURE="echo -en \\\\033\[1;31m"  
SET COLOR\_WARNING="echo -en \\\\033\[1;33m"  
SET COLOR\_NORMAL="echo -en \\\\033\[0;39m"  
echo ----oldboy trainning-----  &&  $SETCOLOR\_SUCCESS  
echo ----oldboy trainning-----  &&  $SETCOLOR\_FAILURE  
echo ----oldboy trainning-----  &&  $SETCOLOR\_WARNING  
echo ----oldboy trainning-----  &&  $SETCOLOR\_NORMAL  
  
\[root@node01 day9\]\# vi echo-color01.sh  
 \#!/bin/bash  
blackcolor='\\E\[1;30m'  
redcolor='\\E\[1;31m'  
greencolor='\\E\[1;32m'  
yellowcolor='\\E\[1;33m'  
bluecolor='\\E\[1;34m'  
purplecolor='\\E\[1;35m'  
cyancolor='\\E\[1;36m'  
whitecolor='\\E\[1;37m'  
echo -e "$\{blackcolor\}black"  
echo -e "$\{redcolor\}red"  
echo -e "$\{greencolor\}green"  
echo -e "$\{yellowcolor\}yellow"  
echo -e "$\{bluecolor\}blue"  
echo -e "$\{purplecolor\}purple"  
echo -e "$\{cyancolor\}cyan"  
echo -e "$\{whitecolor\}white"  
  
三、例子：根据用户的选择输入是那种水果并加上不同的颜色  
执行脚本打印一个水果菜单如下：  
1、apple  
2、pear  
3、banana  
4、cherry  
当用户选择水果的时候，打印告诉它选择的水果是什么，并给说过单词加上一种颜色，要求用case语句实现  
\[root@node01 day9\]\# vi fruit\_memu.sh   
\#!/bin/sh  
redcolor='\\E\[1;31m'  
greencolor='\\E\[1;32m'  
yellowcolor='\\E\[1;33m'  
RES='\\E\[0m'  
function fruit\_menu()\{  
cat <<END  
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
END  
\}  
while true  
do  
fruit\_menu  
read -p "pls input your choice:" fruit  
case "$fruit" in  
   1)  
     echo -e "$redcolor apple $RES"  
     ;;  
   2)  
     echo -e "$greencolor pear $RES"  
     ;;  
   3)  
     echo -e "$yellowcolor banana $RES"  
     ;;  
   4)  
     exit 0  
     ;;  
   \*)  
     echo -e "no fruit you choose."  
esac  
done  
~                                                                                                                                                                        
"fruit\_memu.sh" 36L, 527C written                                                                                                                      
\[root@node01 day9\]\# sh fruit\_memu.sh   
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:1  
 apple   
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:2  
 pear   
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:3  
 banana   
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:4  
\[root@node01 day9\]\#   
\[root@node01 day9\]\#   
\[root@node01 day9\]\#   
\[root@node01 day9\]\# sh fruit\_memu.sh   
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:5  
no fruit you choose.  
=======================  
1、apple  
2、pear  
3、banana  
4、exit  
=======================  
pls input your choice:  
  
四、开发一个给指定内容加指定颜色的脚本  
要求：  
1、使用read或者传参实现。  
2、以传参为例：在脚本行传2个参数，给指定内容（是第一个参数）加指定的颜色（是第二个参数）。  
\[root@node01 day9\]\# cat fruit\_memu.sh   
\#!/bin/sh  
red\_color='\\E\[1;31m'  
green\_color='\\E\[1;32m'  
yellow\_color='\\E\[1;33m'  
blue\_color='\\E\[1;34m'  
pink\_color='\\E\[1;35m'  
RES='\\E\[0m'  
if \[ $\# -ne 2 \];then  
   echo "Usage $0 centent \{red|yellow|blue|green\}"  
   exit  
fi  
case "$2" in  
  red|RED)  
     echo -e "$\{red\_color\}$1$\{RES\}"  
     ;;  
  yellow|YELLOW)  
     echo -e "$\{green\_color\}$1$\{RES\}"  
     ;;  
  blue|BLUE)  
     echo -e "$\{yellow\_color\}$1$\{RES\}"  
     ;;  
  green|GREEN)  
     echo -e "$\{blue\_color\}$1$\{RES\}"  
     ;;  
  pink|PINK)  
     echo -e "$\{pink\_color\}$1$\{RES\}"  
     ;;  
   \*)  
     echo "Usage $0 centent \{red|yellow|blue|green\}"  
     exit  
esac  
\[root@node01 day9\]\# sh plus\_color.sh wolf red  
wolf  
\[root@node01 day9\]\# sh plus\_color.sh laolang yellow  
laolang  
\[root@node01 day9\]\# sh plus\_color.sh zhangs blue  
zhangs  
\[root@node01 day9\]\# sh plus\_color.sh dd pink  
dd  
  
使用以上脚本改为函数加颜色  
\[root@node01 day9\]\# vi plus\_color\_fun.sh   
\#!/bin/sh  
plus\_color()\{  
red\_color='\\E\[1;31m'  
green\_color='\\E\[1;32m'  
yellow\_color='\\E\[1;33m'  
blue\_color='\\E\[1;34m'  
pink\_color='\\E\[1;35m'  
RES='\\E\[0m'  
if \[ $\# -ne 2 \];then  
   echo "Usage $0 centent \{red|yellow|blue|green\}"  
   exit  
fi  
case "$2" in  
  red|RED)  
     echo -e "$\{red\_color\}$1$\{RES\}"  
     ;;  
  yellow|YELLOW)  
     echo -e "$\{green\_color\}$1$\{RES\}"  
     ;;  
  blue|BLUE)  
     echo -e "$\{yellow\_color\}$1$\{RES\}"  
     ;;  
  green|GREEN)  
     echo -e "$\{blue\_color\}$1$\{RES\}"  
     ;;  
  pink|PINK)  
     echo -e "$\{pink\_color\}$1$\{RES\}"  
     ;;  
   \*)  
     echo "Usage $0 centent \{red|yellow|blue|green\}"  
     exit  
esac  
\}  
  
plus\_color "I" red  
plus\_color "am" blue  
plus\_color "wolf" green  
"plus\_color\_fun.sh" 37L, 681C written                                                                                                                  
You have new mail in /var/spool/mail/root  
\[root@node01 day9\]\# sh plus\_color\_fun.sh   
I  
am  
wolf  
  
五、利用case语句开发类是系统启动rsync服务的脚本（可参考系统的rpcbind/nfs/crond）  
例如：/etc/init.d/rsyncd (start|stop|restart)  
rsync --daemon  
lsof -i :873  
=========================================  
\[root@node01 day10\]\# cat /etc/rsyncd.conf  
uid = rsync  
gid = rsync  
use chroot = no  
max connections = 200  
timeout = 300  
pid file = /var/run/rsync.pid  
lock file = /var/run/rsync.lock  
log file = /var/log/rsync.log  
\[wolf\]  
path = /data/  
ignore errors = yes  
read only = false  
write only = false  
hosts allow = 192.168.0.0/16  
hosts deny = \*  
list = false  
auth users = rsync  
secrets file = /etc/rsync.passwd  
=========================================  
\[root@node01 day10\]\# cat rsyncd.sh   
\#!/bin/sh  
. /etc/init.d/functions  
pidfile=/var/run/rsync.pid  
function start\_rsync()\{  
if \[ -f "$pidfile" \]  
     then  
       echo "rsync is running"  
else  
          rsync --daemon  
       echo "rsync is started"    
fi  
\}  
function stop\_rsync()\{  
if \[ -f "$pidfile" \]  
     then  
       kill -9 \`cat $pidfile\`  
       rm -f $pidfile  
       echo "rsync is stopped"  
else  
       echo "rsync no running"  
fi    
\}  
function usage()\{  
   echo "USAGE:$0 \{start|stop|restart\}"  
   exit 1  
\}  
case "$1" in  
  start)  
        start\_rsync  
        RETVAL=$?  
        ;;  
  stop)  
        stop\_rsync  
        RETVAL=$?  
        ;;  
  restart)  
        stop\_rsync  
        sleep 2  
        start\_rsync  
        RETVAL=$?  
        ;;  
   \*)  
    usage  
esac  
\[root@node01 day10\]\# sh rsyncd.sh start  
rsync is started  
\[root@node01 day10\]\# lsof -i :873        
COMMAND   PID USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME  
rsync   46561 root    4u  IPv4 1244539      0t0  TCP \*:rsync (LISTEN)  
rsync   46561 root    5u  IPv6 1244540      0t0  TCP \*:rsync (LISTEN)  
\[root@node01 day10\]\# sh rsyncd.sh stop   
rsync is stopped  
\[root@node01 day10\]\# lsof -i :873       
You have new mail in /var/spool/mail/root  
\[root@node01 day10\]\# sh rsyncd.sh rstart  
USAGE:rsyncd.sh \{start|stop|restart\}  
\[root@node01 day10\]\# sh rsyncd.sh restart  
rsync is running  
rsync is started  
\[root@node01 day10\]\# lsof -i :873          
COMMAND   PID USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME  
rsync   46577 root    4u  IPv4 1244705      0t0  TCP \*:rsync (LISTEN)  
rsync   46577 root    5u  IPv6 1244706      0t0  TCP \*:rsync (LISTEN)  
  
优化脚本  
\#!/bin/sh  
\# chkconfig: 2345 34 61  
\# description: start rsync and stop rsync scripts.  
. /etc/init.d/functions  
pidfile=/var/run/rsync.pid  
function start\_rsync()\{  
if \[ -f "$pidfile" \]  
     then  
       echo "rsync is running"  
else  
          rsync --daemon  
       action "rsync is started" /bin/true  
fi  
\}  
function stop\_rsync()\{  
if \[ -f "$pidfile" \]  
     then  
       kill -9 \`cat $pidfile\`  
       rm -f $pidfile  
       action "rsync is stopped" /bin/true  
else   
       action "rsync no running" /bin/false  
fi    
\}  
function usage()\{  
   echo "USAGE:$0 \{start|stop|restart\}"  
   exit 1  
\}  
case "$1" in  
  start)  
        start\_rsync  
        RETVAL=$?  
        ;;  
  stop)  
        stop\_rsync  
        RETVAL=$?  
        ;;  
  restart)  
        stop\_rsync  
        sleep 2  
        start\_rsync  
        RETVAL=$?  
        ;;  
   \*)  
    usage  
esac  
\[root@node01 day10\]\# sh rsyncd.sh restart  
rsync is stopped                                           \[  OK  \]  
rsync is started                                           \[  OK  \]  
\[root@node01 day10\]\# sh rsyncd.sh stop  
rsync is stopped                                           \[  OK  \]  
\[root@node01 day10\]\# sh rsyncd.sh stop  
rsync no running                                           \[FAILED\]  
\[root@node01 day10\]\# sh rsyncd.sh stop  
rsync no running                                           \[FAILED\]  
\[root@node01 day10\]\# sh rsyncd.sh start  
rsync is started                                           \[  OK  \]  
  
加入自启动  
cp rsyncd.sh /etc/init.d/rsyncd  
\[root@node01 day10\]\# chkconfig --add rsyncd  
\[root@node01 day10\]\# chkconfig --list  
\[root@node01 day10\]\# ll /etc/rc.d/rc3.d/|grep 34