windows echo 命令在批处理编程中是如何工作的
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How does the echo command works in batch programming
提问by BAR Software
I'm have started to learn batch programming to go a little more deeper in the Windows Machines. In Internet I have seen some commands with echo like "@echo off"or "on"and also this: "echo."but I don't know what are they doing. If anyone can explain me the functions of the echo command, please answer me.
我已经开始学习批处理编程，以便在 Windows 机器上更深入一些。在 Internet 上，我看到了一些带有 echo 的命令，例如“@echo off”或“on”，还有这个：“echo”。但我不知道他们在做什么。如果有人可以向我解释 echo 命令的功能，请回答我。
回答by Antonio Gschossmann
The ECHO command in Windows CMD is used to print out text to the screen, display the actual setting of the Command-line which means when you do:
Windows CMD 中的 ECHO 命令用于将文本打印到屏幕上，显示命令行的实际设置，这意味着当您执行以下操作时：
@echo off
The "C:\Users[User]"line before your command input will disappear. You can restore it with:
命令输入之前的“C:\Users[User]”行将消失。您可以通过以下方式恢复它：
@echo on
Here all functions of ECHO explained:
ECHO的所有功能在这里解释：
@echo [on/off](to set the command-line settings)
echo [text](to print text to the screen)
echo.(to print an empty line to the screen)
echo(displays the current setting of the command-line)
echo /?(displays help for the command ECHO)
@echo [on/off]（设置命令行设置）
echo [text]（将文本打印到屏幕上）
回声。（在屏幕上打印一个空行）
echo（显示命令行的当前设置）
回声 /? （显示命令 ECHO 的帮助）
I hope I was able to help you.
我希望我能帮到你。
回答by Harun
By default, every command executed in a batch file is also echoed to the output - not just the output of the command, but the command itself.
默认情况下，批处理文件中执行的每个命令也会回显到输出 - 不仅是命令的输出，还有命令本身。
The echo command has three modes:
echo 命令具有三种模式：
- When called with some arguments AFTER a space, it will output the arguments.
- When called as
echo.(no space) it will output just a blank line. - When called with just the arguments on or off, it controls the behaviour of printing the commands as they execute.*
- 当在空格后使用一些参数调用时，它将输出参数。
- 当调用为
echo.（无空格）时，它只会输出一个空行。 - 当仅使用 on 或 off 参数调用时，它控制在命令执行时打印命令的行为。*
So, the echo offcommand turns off the output at the start of the batch file. However, that command itself is still echoed before it has a chance to turn off the echoing. The @ symbol has the effect of turning off the output for only the current command.
因此，该echo off命令在批处理文件的开头关闭输出。然而，在它有机会关闭回显之前，该命令本身仍然被回显。@ 符号的作用是仅关闭当前命令的输出。
Combining the two, the @echo offat the start of a batch file turns off the echoing without itself being echoed.
将两者结合起来，@echo off在批处理文件的开头关闭回显而不回显本身。
(* I'm not sure exactly how to output the text "on" or "off", but I suspect that using quotes around the text will change the behaviour.)
（* 我不确定如何输出文本“on”或“off”，但我怀疑在文本周围使用引号会改变行为。）
回答by lostbard
Partial answer is this: What does "@" mean in Windows batch scripts
部分答案是：Windows 批处理脚本中的“@”是什么意思
The @ before the command means do not print that command when running it.
命令前的@ 表示在运行该命令时不打印该命令。
The off argument tells the script not output any other commands, however without the @ would output the echo off (since echoing hasn't yet been turned off)
off 参数告诉脚本不输出任何其他命令，但是没有 @ 会输出 echo off（因为 echo 尚未关闭）
The on argument turns command echoing back on.
on 参数将命令回显重新打开。
Any other arguments are just echoed to the display
任何其他参数只是回显到显示器
