如何在Windows的命令提示符下睡5秒钟? (或DOS)
这个问题在这里已经有了答案:
我看到的一个黑客是(错误)使用ping命令:
ping 127.0.0.1 -n 6 > nul
127.0.0.1
是本地主机IP地址。
-n 6
- 每次ping之间有1秒的延迟,所以对于5秒的延迟,你需要做6个ping。
> nul
- 抑制输出。
我很惊讶没有人提到过:
C:> timeout 5
NB请注意但是(感谢丹!) timeout 5
意味着:
在4到5秒之间的任何地方睡觉
这可以通过将以下内容放入批处理文件中,反复运行并计算第一个和第二个echo
之间的时间差来验证:
@echo off
echo %time%
timeout 5 > NUL
echo %time%
尝试选择命令。 从MSDOS 6.0开始就已经出现了,并且应该做到这一点。
使用/ T参数指定以秒为单位的超时值,使用/ D参数指定默认选择并忽略所选的选项。
这可能是一个问题,如果用户在超时时间过去之前键入其中一个选择字符。 部分解决方法是混淆这种情况 - 使用/ N参数来隐藏有效选项列表,并且只在该组选项中包含1个字符,所以用户将不太可能在超时到期。
以下是Windows Vista上的帮助文字。 我认为它在XP上是一样的,但请查看XP计算机上的帮助文本进行验证。
C:>CHOICE /?
CHOICE [/C choices] [/N] [/CS] [/T timeout /D choice] [/M text]
Description:
This tool allows users to select one item from a list
of choices and returns the index of the selected choice.
Parameter List:
/C choices Specifies the list of choices to be created.
Default list is "YN".
/N Hides the list of choices in the prompt.
The message before the prompt is displayed
and the choices are still enabled.
/CS Enables case-sensitive choices to be selected.
By default, the utility is case-insensitive.
/T timeout The number of seconds to pause before a default
choice is made. Acceptable values are from 0 to
9999. If 0 is specified, there will be no pause
and the default choice is selected.
/D choice Specifies the default choice after nnnn seconds.
Character must be in the set of choices specified
by /C option and must also specify nnnn with /T.
/M text Specifies the message to be displayed before
the prompt. If not specified, the utility
displays only a prompt.
/? Displays this help message.
NOTE:
The ERRORLEVEL environment variable is set to the index of the
key that was selected from the set of choices. The first choice
listed returns a value of 1, the second a value of 2, and so on.
If the user presses a key that is not a valid choice, the tool
sounds a warning beep. If tool detects an error condition,
it returns an ERRORLEVEL value of 255. If the user presses
CTRL+BREAK or CTRL+C, the tool returns an ERRORLEVEL value
of 0. When you use ERRORLEVEL parameters in a batch program, list
them in decreasing order.
Examples:
CHOICE /?
CHOICE /C YNC /M "Press Y for Yes, N for No or C for Cancel."
CHOICE /T 10 /C ync /CS /D y
CHOICE /C ab /M "Select a for option 1 and b for option 2."
CHOICE /C ab /N /M "Select a for option 1 and b for option 2."
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