调试 Windows 命令行语法错误答案

【问题标题】：Debugging Windows Command Line Syntax Error调试 Windows 命令行语法错误
【发布时间】：2018-04-09 03:08:42
【问题描述】：

我正在学习 Windows 命令行课程，但我在批处理文件中收到一条我不理解的错误消息。我应该创建一个批处理文件，它接受参数并打印它们是否是环境变量。这是我目前所拥有的：

::  Disable echoing of batch file commands to console.
@echo off

rem ********Begin Header******************
::  Author:     Megan
::  Date:   04/08/2018
::  File:   checkVars.bat
::  Descr:
::  This script determines if a given
::  set of arguments are defined
::  environmental variables.
rem ********End Header********************

::  Check to make sure at least one command
::  line argument has been given. If not,
::  display a usage message and exit the 
::  batch file. 
if "%1" == "" (
   echo Usage: %0 varname1 ...
   echo Determines if variable name is defined
   exit /b 1
)

:: determine if arguments %1 and greater
:: are environmental variables
:again
if not "%1" == "" (
   if defined %1 (
      echo %1 is a defined environment variable.
      echo.
   ) else (
      echo %1 is NOT a defined environment variable.
      echo.
   )
   shift /1
   goto again
)

当我使用命令 checkVars windir mydir prompt myvar 运行批处理文件时，我得到以下输出：

windir is a defined environmental variable.

mydir is NOT a defined environmental variable.

prompt is a defined environmental variable.

myvar is NOT a defined environmental variable.

The syntax of the command is incorrect.

看起来我的代码运行了一次额外的时间。谁能帮我指出错误的方向？

【问题讨论】：

标签： batch-file command-line syntax-error

【解决方案1】：

查看您的代码后，我注意到您需要用引号将某些部分括起来。导致语法错误的主要原因是if defined %1，其中%1 需要变为"%1"。希望这能解决您的问题。

更正的代码：

::  Disable echoing of batch file commands to console.
@echo off

rem ********Begin Header******************
::  Author:     Megan
::  Date:   04/08/2018
::  File:   checkVars.bat
::  Descr:
::  This script determines if a given
::  set of arguments are defined
::  environmental variables.
rem ********End Header********************

::  Check to make sure at least one command
::  line argument has been given. If not,
::  display a usage message and exit the 
::  batch file. 
if "%1" == "" (
   echo Usage: %0 varname1 ...
   echo Determines if variable name is defined
)

:: determine if arguments %1 and greater
:: are environmental variables
:again
if not "%1" == "" (
   if defined "%1" (
      echo %1 is a defined environment variable.
      echo.
   ) else (
      echo %1 is NOT a defined environment variable.
      echo.
   )
   shift /1
   goto again
)

【讨论】：