如何在启动/调用批处理文件时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

我正在尝试在批处理文件中使用以下验证逻辑，但即使没有向批处理文件提供参数，使用"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

我做错了什么?

推荐答案

检查命令行参数是否已设置可以[%1]==[]，但是，如戴夫·科斯塔 指出，"%1"==""也会工作.

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

我还修复了使用 echo 中的语法错误以转义大于号和小于号.此外，exit 需要一个 /B 参数，否则 CMD.exe 将退出.

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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