bash腳本編程實例

bash腳本編程實例

• 1.寫一個腳本
  • 能接受四個參數：start、stop、restart、status
  • start：輸出“starting腳本名finished.”
  • restart：輸出“restarting腳本名finished.”
  • stop：輸出“stoping腳本名finished.”
  • status：輸出“status腳本名finished.”
  • 其他任意參數，均報錯退出

    #!/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.寫一個腳本，判斷給定的用戶是否登錄了當前系統

  • 如果登錄了，則顯示用戶登錄，腳本終止

  • 每三秒鐘，查看一次用戶是否登錄

    #!/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.寫一個腳本，顯示用戶選定要查看的信息

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

  • 非此四項選擇，則提示錯誤，并要求用戶重新選擇，直到其給出正確的選擇為止

    #!/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.寫一個腳本

  • 用函數實現返回一個用戶的ID和SHELL；用戶名通過參數傳遞而來
  • 提示用戶輸入一個用戶名或者輸入“quit”退出
  • 當輸入的是用戶名，則調用函數顯示用戶信息

  • 當用戶輸入quit，則退出腳本，進一步地，顯示鍵入的用戶相關信息后，再次提醒輸出用戶名或者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