批处理脚本 - 返回代码

返回码是程序执行时返回的代码。如果命令行成功，它应该返回零；如果不成功，它应该返回非零。如果测试失败，一个非零值表示错误号，用户可以尝试通过导航到错误消息来解决它。

测试也可能返回退出代码。程序或实用程序的退出代码通常在完成或终止时出现。

下面的列表包括程序可能返回的一些非零退出代码（及其各自的错误）

Error Code	Description
0	Successful completion of the program.
1	This error indicates that the Windows command prompt has attempted to execute an unrecognized action
2	An error indicating that the file could not be found in the specified location
3	An error message indicated that the specified path could not be found.
5	An indication that the user is not authorized to access the resource
90090×2331	This error occurs when you misspell the command, application name, or path when configuring an Action.
2212254950xC0000017-1073741801	The error message tells you that Windows has run out of memory.
32212257860xC000013A-1073741510	This indicates that the user terminated the application
32212257940xC0000142-1073741502	The message indicating that the application was launched on a desktop to which the current user doesn’t have access

批处理文件错误级别：

%ERRORLEVEL% 是一个环境变量，包含批处理文件中的最后一个错误级别或返回代码——即最后执行的命令的最后一个错误代码。可以使用%ERRORLEVEL%变量检查错误级别，如下所示：

IF %ERRORLEVEL% NEQ 0 (
  DO_Something
)

从批处理文件返回错误代码的常用方法是使用命令EXIT /B %ERRORLEVEL%。

对于自定义返回代码，请使用EXIT /B 命令。

在下面的示例中，如果满足条件，则脚本将以退出代码 0 终止。如果不满足条件，则退出代码将为 1。

if [[ "$(whoami)" != root ]]; then
   echo "Not root user."
   exit 1
fi
echo "root user"
exit 0

输出：

输出

在决策一章中依次颁布了声明。或者，批处理脚本也可用于更改程序逻辑中的控制流。然后将这些语句组织成流控制语句。

Serial No	Loops	Description
1	While Statement Implementation	There is no direct while statement in Batch Script, although labels and an if statement can be used to implement this loop.
2	For Statement – List Implementations	Batch files can loop using the “FOR” construct. In order to work with a list of values, the ‘for’ statement requires the following construct.
3	Looping through Ranges	‘For’ statements can also move through ranges of values. A general version is presented below.
4	Classic for Loop Implementation	It has the classic ‘for’ statement found in many programming languages.
5	Break Statement Implementation	Within any programming language, the break statement is used to alter the flow of control inside a loop. As part of looping constructs, the break statement causes the innermost enclosing loop to terminate immediately

要检查命令行参数，可以使用 for 语句。这是一个如何使用“for”语句循环命令行参数的示例。

for ((c=1; c<=7; c++))
do  
  echo "Welcome $c times"
done

输出：

输出