启动/调用批处理文件时，如何检查是否定义了参数? [英] How can I check if an argument is defined when starting/calling a batch file?

问题描述

我试图在批处理文件中使用以下验证逻辑，但是即使未向批处理文件提供任何参数，"usage"块也永远不会执行.

I'm trying to use the following validation logic in a batch file but the "usage" block never executes even when no parameter is supplied to the batch file.

if ("%1"=="") goto usage

@echo This should not execute

@echo Done.
goto :eof

:usage
@echo Usage: %0 <EnvironmentName>
exit 1

我在做什么错了?

推荐答案

检查是否已设置命令行参数可以为[%1]==[]，但可以为指出，"%1"==""也将起作用.

The check for whether a commandline argument has been set can be [%1]==[], but, as Dave Costa points out, "%1"=="" will also work.

我还修复了用法回显中的语法错误，以避开大于和小于符号.另外，exit需要一个/B参数，否则CMD.exe将会退出.

I also fixed a syntax error in the usage echo to escape the greater-than and less-than signs. In addition, the exit needs a /B argument otherwise CMD.exe will quit.

@echo off

if [%1]==[] goto usage
@echo This should not execute
@echo Done.
goto :eof
:usage
@echo Usage: %0 ^<EnvironmentName^>
exit /B 1

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