Shell小程序一个

if [ $? -eq 0 ] ; then
	echo "Command was successful";
else
	echo "An error was encountered";
exit
fi

上一条命令的退出状态保存在变量$?中。

记住退出代码为0表示成功。

附上：

四、流控制
        if语句
            文件测试
            字符串比较
            数字比较
            复合表达式
        case语句
          case word in
                   pattern1)
                                 list1
                                 ;;
                   pattern2)
                                 list2
                                 ;;
                   ...
                   patternN)
                                 listN
                                 ;;
          esac
五、循环
    while循环
        while cmd
        do
            list
        done
        1嵌套while循环
        2while中合法的用户输入 P129
        3输入重定向和while
         while和子shel
        4until循环
    for 循环
          for和select循环
          for name in word1 word2 ... wordN
          do
              list
          done
          操作一组文件
    select循环
            select name in word1 word2 ... wordN
          do
              list
          done
          select循环的例子
          改变提示符
    循环控制
             无限循环和break命令
             退出嵌套循环
             continue命令