中国DOS联盟

Format: if exist file name　 command to be executed
If the specified file exists, the condition is true, and the command is run; otherwise, the next sentence is run

If there are two or more commands to be executed, how should they be written?

Another question:
Find a segment of statements to have the following effect.
If 01.txt and 02.txt exist simultaneously under D:\
Then open the contents of 01.txt and 02.txt
Otherwise, delete 01.txt (or 02.txt) when only 01.txt or 02.txt exists

Looking forward to an answer~~~

if exist 1.txt if exist 2.txt (start "" 1.txt && start "" 2.txt)

@echo off

    dir /a-d 1.txt || goto next

    dir /a-d 2.txt || goto next

    start "" 1.txt & start "" 2.txt

goto :eof



:next

    del 1.txt 2.txt 2>nul

goto :eof

1.

if exist 1.txt if exist 2.txt (start "" 1.txt && start "" 2.txt)

2.

@echo off

    dir /a-d 1.txt || goto next

    dir /a-d 2.txt || goto next

    start "" 1.txt & start "" 2.txt

goto :eof



:next

    del 1.txt 2.txt 2>nul

goto :eof

The code has not been tested...

Thanks. . .
Let's try first.

@echo off

if exist 1.txt if exist 2.txt (start "" 1.txt && start "" 2.txt) else (del 1.txt 2.txt 2>nul)

Merge the code for 2F, which should meet the LZ's requirement:

@echo off

if exist 1.txt if exist 2.txt (start "" 1.txt && start "" 2.txt) else (del 1.txt 2.txt 2>nul)

What is the usage of || here? Is it a logical operation?
And what does the '''' in front of 1.txt mean?

& 	command1 & command2	用来分隔一个命令行中的多个命令。Cmd.exe 运行第一个命令，然后运行第二个命令。

&& 	command1 && command2	只有在符号 && 前面的命令成功时，才用于运行该符号后面的命令。Cmd.exe 运行第一个命令，然后只有在第一个命令运行成功时才



运行第二个命令。

|| 	command1 || command2	只有在符号 || 前面的命令失败时，才用于运行符号 || 后面的命令。Cmd.exe 运行第一个命令，然后只有在第一个命令未能运行成



功（接收到大于零的错误代码）时才运行第二个命令。

( ) 	(command1 & command2) 	用来分组或嵌套多个命令。

; 或者 ，	command1 parameter1;parameter2	用来分隔命令参数。

 注意

	“与”符号 (&)、管道符号 (|) 以及括号 () 是特殊字符，将它们作为参数传递时，必须在其前面加上转义字符 (^) 或引号。 

	如果某个命令成功完成操作，则该命令就返回零 (0) 退出代码或不返回任何退出代码。有关退出代码的详细信息，请参阅 Microsoft Windows Resource Kit。

START      

       

        

      



    "title"     在窗口标题栏中显示的标题。

　　……

1、

& 	command1 & command2	Used to separate multiple commands in a command line. Cmd.exe runs the first command and then the second command.

&& 	command1 && command2	Used to run the command after the && only if the command before the && is successful. Cmd.exe runs the first command and then runs the second command only if the first command runs successfully.

|| 	command1 || command2	Used to run the command after the || only if the command before the || fails. Cmd.exe runs the first command and then runs the second command only if the first command fails to run successfully (receives an error code greater than zero).

( ) 	(command1 & command2) 	Used to group or nest multiple commands.

; or ,	command1 parameter1;parameter2	Used to separate command parameters.

Note

The "and" symbol (&), pipe symbol (|), and parentheses () are special characters. When passing them as parameters, you must prefix them with the escape character (^) or quotes.

If a command successfully completes an operation, the command returns a zero (0) exit code or no exit code. For detailed information about exit codes, refer to the Microsoft Windows Resource Kit.

　　2、

START      

       

        

      



    "title"     The title displayed in the window title bar.

　　……

When the filename is a path with spaces, you must enclose the path in quotes. At this time, in order to prevent start from treating the path as the title, insert a pair of quotes between start and the path to distinguish the title from the path.

Um, learning. Thanks

if  exist filename.txt (

	echo 1

	echo 2

	echo 3

  ) else (

	echo 4

	echo 5

	echo 6

)

if  exist filename.txt (

	echo 1

	echo 2

	echo 3

  ) else (

	echo 4

	echo 5

	echo 6

)

This format might be more convenient to use.