bash脚本编程实例

bash脚本编程实例

• 1.写一个脚本
  • 能接受四个参数：start、stop、restart、status
  • start：输出“starting脚本名finished.”
  • restart：输出“restarting脚本名finished.”
  • stop：输出“stoping脚本名finished.”
  • status：输出“status脚本名finished.”
  • 其他任意参数，均报错退出

    #!/bin/bash
    case $1 in
    start)
    echo "starting ${0} finished."
    ;;
    stop)
    echo "stoping ${0} finished."
    ;;
    restart)
    echo "restarting ${0} finished."
    ;;
    status)
    echo "status ${0} finished."
    ;;
    *)
    echo "error input."
    exit 1
    ;;
    esac

• 2.写一个脚本，判断给定的用户是否登录了当前系统

  • 如果登录了，则显示用户登录，脚本终止

  • 每三秒钟，查看一次用户是否登录

    #!/bin/bash
    if [ $# -eq 0 ];then
     echo "there is no username inputing."
     exit 1
    fi
    
    while true;do
     if id $1 &> /dev/null;then
         user=$(who|grep "^$1"|cut -d' ' -f1)
         if [[ $user == $1 ]];then
             echo "$1 has logined."
             break
         else
             sleep 3
         fi
     else
        echo "there is no user like $1."
        exit 2
    fi
    done

• 3.写一个脚本，显示用户选定要查看的信息

  • cpu）display cpu info
  • mem）display memory info
  • disk）display disk info
  • quit）quit

  • 非此四项选择，则提示错误，并要求用户重新选择，直到其给出正确的选择为止

    #!/bin/bash
    cat << EOF
    cpu)display cpu info
    mem)display memory info
    disk)display disk info
    quit)quit
    EOF
    
    read -p "please input:" ops
    
    while true;do
     if [ $ops != "cpu" -a $ops != "mem" -a $ops != "disk" -a ops != "quit" ];then
       read -p "please input again:" ops
     else
       break
     fi
    done
    
    case $ops in
    cpu)
      lscpu
    ;;
    mem)
      free -m
    ;;
    disk)
      fdisk -l
    ;;
    quit)
      exit 0
    ;;
    esac

• 4.写一个脚本

  • 用函数实现返回一个用户的ID和SHELL；用户名通过参数传递而来
  • 提示用户输入一个用户名或者输入“quit”退出
  • 当输入的是用户名，则调用函数显示用户信息

  • 当用户输入quit，则退出脚本，进一步地，显示键入的用户相关信息后，再次提醒输出用户名或者quit

    #!/bin/bash
    
    userinfo(){
     if [ -z $1 ];then
         return 1
     elif id $param &>> /dev/null;then
         echo "$1 ID is $(id -u $1)."
         echo "$1 shell is $(grep "^$1" /etc/passwd|cut -d: -f7)"
     else
         return 1
     fi
    
    }
    
    while true;do
     read -p "please input a username or quit:" param
     if [[ $param == "quit" ]];then
        exit 0
     else
        userinfo $param
        [ $? -eq 1 ]&&echo "no user named $1."
     fi
    done