Shell流程控制
1.流程控制语句if
单分支结构
f [ 如果你有房 ];then 我就嫁给你 fi双分支结构
if [ 如果你有房 ];then 我就嫁给你 else 再见 fi多分支结构
if [ 如果你有房 ];then 我就嫁给你 elif [ 你有车 ];then 我就嫁给你 elif [ 你有钱 ];then 我就嫁给你 else 再见 fi1.实例, 安装Nginx
#!/usr/bin/bash # Install Nginx # By x86cloud 2018-05-16 ####1.判断网络 ping -c1 www.baidu.com &>/dev/null if [ $? -ne 0 ];then echo "请检查你的网络......" exit 1 fi #2.yum仓库 yum_repo=$(yum repolist|grep nginx|wc -l) if [ $yum_repo -eq 0 ];then cat >/etc/yum.repos.d/nginx.repo <<-EOF [nginx] name=nginx repo baseurl=http://nginx.org/packages/centos/7/x86_64/ gpgcheck=0 enabled=1 EOF yum makecache elif [ $yum_repo -eq 1 ];then yum install nginx -y &>/dev/null Install_nginx=$(rpm -q nginx|wc -l) if [ $Install_nginx -eq 1 ];then echo "Nginx已经安装" fi Nginx_Status=$(systemctl status nginx|grep Active|awk '{print $1 $3}') systemctl start nginx &>/dev/null if [ $? -eq 0 ];then echo "Nginx已经启动完毕" echo "Nginx当前状态是: $Nginx_Status" else echo "Nginx启动失败 $Nginx_Status" pkill -9 httpd &>/dev/null pkill -9 nginx &>/dev/null systemctl start nginx if [ $? -eq 0 ];then echo -e "Nginx重新启动成功" Nginx_Status=$(systemctl status nginx|grep Active|awk '{print $1 $3}') echo -e "\033[32m $Nginx_Status \033[0m" fi fi else echo "不知道什么错误，请手动检查下" fi2.根据不同的系统安装不同的yum源
#!/usr/bin/bash os_name=$(cat /etc/redhat-release) os_version=$(cat /etc/redhat-release |awk '{print $4}'|awk -F '.' '{print $1}') if [ $os_version = "(Final)" ];then os_version=$(cat /etc/redhat-release |awk '{print $3}'|awk -F '.' '{print $1}') fi if [ $os_version -eq 7 ];then mkdir -p /etc/yum.repos.d/backup mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup cat >/etc/yum.repos.d/base.repo<<-EOF [base] name=Local Base Yum Source baseurl=ftp://192.168.56.1/base/7/x86_64 enable=1 gpgcheck=0 EOF echo "$os_name 系统已经配置好yum仓库" elif [ $os_version -eq 6 ];then mkdir -p /etc/yum.repos.d/backup mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo &>/dev/null echo "$os_name 系统已经配置好yum仓库" elif [ $os_version -eq 5 ];then mkdir -p /etc/yum.repos.d/backup mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo &>/dev/null echo "$os_name 系统已经配置好yum仓库" else echo "无法检测当前系统版本,请检查/etc/redhat-release" fi3.安装不同版本的PHP
#!/usr/bin/bash #install php install_php56() { echo "install php5.6......" } install_php70() { echo "install php7.0......" } install_php71() { echo "install php7.1......" } while : do echo "################################" echo -e "\t1 php-5.6" echo -e "\t2 php-7.0" echo -e "\t3 php-7.1" echo -e "\tq exit" echo "################################" read -p "version[1-3]: " version if [ "$version" = "1" ];then install_php56 elif [ "$version" = "2" ];then install_php70 elif [ "$version" = "3" ];then install_php71 elif [ "$version" = "q" ];then exit else echo "error" fi done
2.流程控制语句case
case语句 case 变量 in 模式 1) 命令序列 1;; 模式 2) 命令序列 2;; 模式 3) 命令序列 3 ;; *) 无匹配后命令序列 esac1.批量删除用户
#!/usr/bin/bash read -p "请输入需要删除的用户前缀，以及用户的位数: " delname delnum echo "你将要删除如下账户 用户前缀是: $delname 用户的个数: $delnum " read -p "你确定要删除吗[y|Y|Yes|n|N|NO]?" reday for i in $(seq $delnum);do userfull=$delname$i case $reday in y|Y|YES) id $userfull &>/dev/null if [ $? -eq 0 ];then userdel $userfull &>/dev/null echo "userdel is ok $userfull...." else echo "$userfull" no such user fi ;; n|N|no|NO|No) exit 1 ;; *) read -p "你确定要删除吗[y|Y|Yes|n|N|NO]?" reday esac done2.系统管理工具箱
Command action
h 显示命令帮助
f 显示磁盘分区
d 显示磁盘挂载
m 查看内存使用
u 查看系统负载
q 退出程序#!/usr/bin/bash caidan(){ cat <<-EOF =================== h 显示命令帮助 f 显示磁盘分区 d 显示磁盘挂载 m 查看内存使用 u 查看系统负载 q 退出程序 ===================== EOF } while true do read -p "请输入你想查看系统状态对应码[d/m/u/q]: " sys case "$sys" in h) clear caidan ;; f) clear lsblk ;; d) clear df -h ;; m) clear free -m ;; u) clear uptime ;; q) break ;; *) echo "error" exit 1; esac done3.实现简单的JumpServer
#!/usr/bin/bash #jumpServer Mysql_master=192.168.70.160 Mysql_slave1=192.168.70.161 Mysql_slave2=192.168.70.162 Nginx_Up=192.168.70.150 Nginx_WEB1=192.168.70.151 Nginx_WEB2=192.168.56.11 meminfo(){ cat <<-EOF ------------------------------- | 1) mysql-master | | 2) mysql-slave1 | | 3) mysql-slave2 | | 4) Nginx-Upstream | | 5) Nginx-WebNode1 | | 6) Nginx-WebNode2 | | h) help | --------------------------------- EOF } #调用函数打印菜单 meminfo #控制不让输入ctrl+c,z trap "" HUP INT TSTP while true do read -p "请输入要连接的主机编号: " num case $num in 1|mysql-master) ssh root@$Mysql_master ;; 2|Mysql_slave1) ssh root@$Mysql_slave1 ;; 3|Mysql_slave2) ssh root@$Mysql_slave2 ;; h|help) clear meminfo ;; #退出脚本后门, 不要让其他人知道 exec) break ;; esac done //无论使用登陆式shell或非登陆式shell都会执行该脚本, 前提root用户不允许登陆 [root@Shell day03]# cat /home/alex/.bashrc sh /home/alex/jumpserver.sh5.使用case编写服务启动与停止脚本
#!/usr/bin/bash # manager Nginx start stop restart reload source /etc/init.d/functions act=$1 te(){ if [ $? -eq 0 ];then action "Nginx Is $act" /bin/true else action "Nginx Is $act" /bin/false fi } start(){ /usr/sbin/nginx &>/dev/null te } stop(){ /usr/sbin/nginx -s stop &>/dev/null te } reload(){ /usr/sbin/nginx -s reload te } status(){ Ngx_status=$(ps aux|grep "[n]ginx"|egrep -v "vi|sh"|grep master|awk '{print $2}') Nginx_Status_Port=$(netstat -lntp|grep nginx|awk '{print $4}') echo "Nginx_status_Pid: $Ngx_status" echo "Nginx_status_Port: $Nginx_Status_Port" } case $1 in start) start ;; stop) stop ;; restart) stop sleep 1 start ;; reload) reload ;; status) status ;; *) echo "Usage: $0 {start|stop|status|restart|reload|}" esac6.使用case实现多级菜单
3.交互脚本expect
1.expect实现简单的交互登陆
#!/usr/bin/expect spawn ssh [email protected] expect { "yes/no" { send "yes\r"; exp_continue } "password:" { send "centos\r" }; } interact2.expect定义变量实现交互方式
#!/usr/bin/expect set ip 192.168.70.161 set user root set password centos set timeout 5 spawn ssh $user@$ip expect { "yes/no" { send "yes\r"; exp_continue } "password:" { send "$password\r" }; } #交互方式 interact3.expect进行参数传递，执行命令或其他操作
#!/usr/bin/expect #位置传参 set ip [lindex $argv 0] set user root set password centos set timeout 5 spawn ssh $user@$ip expect { "yes/no" { send "yes\r"; exp_continue } "password:" { send "$password\r" }; } #当出现#号符执行如下命令 expect "#" send "useradd bgx\r" send "pwd\r" send "exit\r" expect eof4.批量获取在线主机, 进行秘钥批量分发
cat for_ip.sh #!/usr/bin/bash #setup1 拿到IP地址 >ip.txt for i in {160..162} do ip=192.168.70.$i { ping -c1 -W1 $ip &>/dev/null if [ $? -eq 0 ];then echo "$ip" >> ip.txt fi }& done #2.生成对应的密钥 if [ ! -f ~/.ssh/id_rsa ];then ssh-keygen -P "" -f ~/.ssh/id_rsa fi #3.批量分发密钥 while read line do /usr/bin/expect <<-EOF set pass 1 set timeout 2 spawn ssh-copy-id $line -f expect { "yes/no" { send "yes\r"; exp_continue} "password:" { send "1\r"} } expect eof EOF done<ip.txt