1、case语句的用法：
[root@ELK-chaofeng test]# cat test3.sh#!/bin/bashwhile true ;doread -p "please input the menu:cpu,mem,disk,quit: " variablecase $variable in cpu) lscpu break ;; mem) free -m break ;; disk) fdisk -l /dev/[shv]d[a-z][0-9] break ;; *) echo "error,again" ;;esacdone
看一下效果
现在我们来编写一个服务框架：
[root@ELK-chaofeng init.d]# cat testservice #!/bin/bash##chkconfig: 2345 60 60#description: test service script#prog=$(basename $0)lockfile=/var/lock/subsys/${prog}case $1 instart) if [ -f $lockfile ];then echo "service $prog is running" else touch $lockfile echo "service $prog start" fi;;stop) if [ -f $lockfile ];then rm -rf $lockfile echo "service $prog stop" else echo "service $prog stop" fi;;restart) if [ -f $lockfile ];then rm -rf $lockfile && touch $lockfile echo "service $prog restart" else touch $lockfile echo "service $prog start" fi;;status) if [ -f $lockfile ];then echo "service $prog is running" else echo "service $prog is not running" fi;;*) echo "usage: $prog {start|restart|stop|status}";;esac 然后chkconfig添加至service服务管理。现在看一下效果：
[root@ELK-chaofeng init.d]# chkconfig --add testservice [root@ELK-chaofeng init.d]# chkconfig --list testservice Note: This output shows SysV services only and does not include native systemd services. SysV configuration data might be overridden by native systemd configuration. If you want to list systemd services use 'systemctl list-unit-files'. To see services enabled on particular target use 'systemctl list-dependencies [target]'.testservice 0:off 1:off 2:on 3:on 4:on 5:on 6:off[root@ELK-chaofeng init.d]# service testservice statusservice testservice is running[root@ELK-chaofeng init.d]# service testservice stopservice testservice stop[root@ELK-chaofeng init.d]# service testservice startservice testservice start[root@ELK-chaofeng init.d]# service testservice statusservice testservice is running[root@ELK-chaofeng init.d]# service testservice stopservice testservice stop[root@ELK-chaofeng init.d]# service testservice statusservice testservice is not running[root@ELK-chaofeng init.d]# service testservice restartservice testservice start[root@ELK-chaofeng init.d]# service testservice statusservice testservice is running
case总结：
case支持glob风格的通配符：、
*：任意长度的任意字符；
？：任意单个字符；
[ ]：范围内任意单个字符；
a|b：a或b
现在我们使用函数来改写上面的脚本：
#!/bin/bash##chkconfig: 2345 60 60#description: test service script#prog=$(basename $0)lockfile=/var/lock/subsys/${prog}start(){ if [ -f $lockfile ];then echo "service $prog is running" else touch $lockfile echo "service $prog start" fi}stop() { if [ -f $lockfile ];then rm -rf $lockfile echo "service $prog stop" else echo "service $prog stop" fi} else touch $lockfile echo "service $prog start" fi}stop() { if [ -f $lockfile ];then rm -rf $lockfile echo "service $prog stop" else echo "service $prog stop" fi}status() { if [ -f $lockfile ];then echo "service $prog is running" else echo "service $prog is not running" fi}usage () { echo "usage: $prog {start|restart|stop|status}"}case $1 instart) start;;stop) stop;;restart) stop start;;status) status;;*) usage;;esac
2、for语句的高级用法：
#!/bin/bash# print 9*9 for ((k=1;k<=9;k++));do for ((i=1;i<=k;i++));do echo -e -n "${i}X${k}=$[${i}*${k}]\t" done echo "" #huan hangdone 看一下效果：
3、while语句的高级用法
#!/bin/bashwhile read VARIABLE;do userID=`echo $VARIABLE | cut -d':' -f 3` userUS=`echo $VARIABLE | cut -d':' -f 1` usershell=`echo $VARIABLE | cut -d':' -f 7` if [ $[$userID%2] -eq 0 ];then echo "$userID,$userUS,$usershell" fidone < /etc/passwd
看一下效果：
