练习9

1.编写函数，实现OS的版本判断

[root@node2 ~]#vi osversion.sh
[root@node2 ~]#cat osversion.sh 
#!/bin/bash
get_os_version () {
    os_version=`sed -r 's/.* ([0-9])\..*/\1/' /etc/redhat-release`
    echo  "$os_version"
}
  
if [ `get_os_version` -eq 6 ];then
       echo "os_version is 6"
       elif [ `get_os_version` -eq 7 ];then
             echo "os_version is 7 "
       elif [ `get_os_version` -eq 5 ];then
              echo "os_version is 5"
fi
[root@node2 ~]#chmod +x osversion.sh 
[root@node2 ~]#./osversion.sh 
os_version is 7

2.编写函数，实现取出当前系统ens32的IP地址

[root@node2 ~]#vi get_ens32_ip.sh
[root@node2 ~]#chmod +x get_ens32_ip.sh 
[root@node2 ~]#./get_ens32_ip.sh 
ip_address=192.168.43.141
[root@node2 ~]#cat get_ens32_ip.sh 
#!/bin/bash
get_ens32_ip () {
      ip=`ifconfig ens32|grep netmask|tr -s ' '|cut -d ' ' -f3`
              echo ip_address=$ip
}
get_ens32_ip

3.编写函数，实现打印绿色OK和红色FAILED
解法一：

[root@node2 ~]#vi print_color.sh
[root@node2 ~]#chmod +x print_color.sh
[root@node2 ~]#./print_color.sh 
success!                                                   [  OK  ]
failed                                                     [FAILED]
[root@node2 ~]#cat print_color.sh 
#!/bin/bash
#
. /etc/init.d/functions
action "success!" true
action "failed"   false

解法二：

[root@node2 ~]#vi print_color2.sh
[root@node2 ~]#chmod +x print_color2.sh 
[root@node2 ~]#./print_color2.sh 
FAILED
OK
[root@node2 ~]#cat print_color2.sh 
#!/bin/bash
print_color2(){
    echo -e "\033[41mFAILED\033[0m"
    echo -e "\033[42mOK\033[0m"
}
print_color2

4.编写函数，实现判断是否无位置参数，如无参数，提示错误

[root@node2 ~]#vi test_para.sh
[root@node2 ~]#chmod +x test_para.sh 
[root@node2 ~]#cat test_para.sh 
#!/bin/bash
para_test () {
    if [ $# -eq 0 ];then
        echo "please input at least a para"
    else 
        echo total $# parameters
    fi
}
para_test a
[root@node2 ~]#cat test_para.sh 
#!/bin/bash
para_test () {
    if [ $# -eq 0 ];then
        echo "please input at least a para"
    else 
        echo total $# parameters
    fi
}
para_test
[root@node2 ~]#./test_para.sh
please input at least a para