如何在命令行中可靠地使用`rem`而不忽略相邻命令？ [英] How to reliably use `rem` within a command line without ignoring adjacent commands?

问题描述

我正在尝试使用 rem 命令在包含多个命令的命令行中放置备注。这里有一些例子来说明我的意思：

I am trying to use the rem command to place a remark in a command line that contains several commands. Here are some examples to illustrate what I mean:

echo Hello & rem.Comment & echo world!

(echo Hello & rem.Comment) & echo world!

这很好用，两个 echo 命令每行都按我的预期执行。 。似乎修改了 rem 命令的行为，因此它不会将其余行视为注释：

This works perfectly fine, both echo commands in each line are executed as I expect. The . seems to modify the behaviour of the rem command so that it does not treat the remaining line as comment:

Hello 
world!

如果我放置了 SPACE （或任何其他定界符 TAB ，，，； ， = ）而不是。，其余行以及第二个 echo 将被忽略。 （在第二个示例中，出现 More？提示，因为）是备注的一部分，而 cmd 预计收盘），因为（）：

If I placed a SPACE (or any other delimiter TAB, ,, ;, =) instead of the ., the remaining line and therefore the second echo would be ignored (for the second example a More? prompt appears, because the ) is part of the remark and cmd expects a closing ) because of the ():

Hello 

我发现除了。，以下字符也起作用：：， / ， \ ， [，] 和 + 。

其他有效的方法是转义分隔符： ^ 空格， ^ TAB ， ^ ，， ^; 和 ^ = 。

I found out that beside ., the following characters work as well: :, /, \, [, ] and +.
What else works is escaped delimiters: ^SPACE, ^TAB, ^,, ^; and ^=.

但是，是否有安全可靠的方法来做到这一点？

我会很高兴看到一个适用于命令提示符和批处理文件的解决方案。

I would be very glad about a solution that works for both command prompt and batch-files.

根据此外部引用，即熟悉的语法 echo。返回空行在某些情况下会失败，因此建议使用 echo（，因为这是唯一可靠的方法。

According to this external reference, the familiar syntax echo. for returning a blank line fails under certain circumstances, hence using echo( is recommended as this is the only reliable method.

但是，对于 rem ，（不起作用， rem（无法识别为命令。

However, for rem, the ( does not work, everything after rem( is not recognised as a command.

因为我知道Windows XP中 rem 命令的怪异错误（参考此外部链接： rem％〜），我对适用于Windows Vista，Windows 7或更高版本的解决方案感兴趣。

Since I am aware of a weird bug of the rem command in Windows XP (reference this external link: rem %~), I am interested in a solution that applies to Windows Vista, Windows 7 or higher.

推荐答案

怪异 REM％〜 bug不是仅限XP。它存在于使用CMD.EXE的Windows的所有现代版本中。阅读完您的问题后，我给SS64的西蒙写了笔记，以澄清问题。如果变量 var 存在，并且您有 rem％var：= ，那么REM也会失败。

The "weird" REM %~ "bug" is not limited to XP. It is present in all modern versions of Windows that use CMD.EXE. After reading your question, I wrote Simon of SS64 a note to give clarification on the issue. REM can also fail if variable var exists, and you have rem %var:=.

因此，从技术上讲，没有保证安全的方法来盲目使用REM。

So technically, there is no guaranteed safe way to blindly use REM.

但是，如果您愿意接受致命的％扩展风险，则列出的大多数产品骇客是可以安全使用的，但仅（如果该行至少包含一个通过& 或&& ; 。

But, if you are willing to accept the fatal % expansion risk, most of your listed hacks are safe to use, but only if the line includes at least one additional command via & or &&.

REM。绝对不会在任何情况下安全使用一个名为 REM （无扩展名）的文件。

REM. is never safe to use in any situation if there exists a file named REM (without extension).

文件夹分隔符 \ test.bat 的文件，并且您使用<和 / 总是失败。 code> REM\..\test.bat 。

The folder dividers \ and / always fail if the current folder contains a file named test.bat and you use REM\..\test.bat.

以类似的方式， REM ：\..\test.bat 总是会失败。

In a similar fashion, REM:\..\test.bat always fails.

在类似情况下，其他所有黑客都可能独立失败。例如， REM ^ [tab] \..\test.bat 独立失败，但如果与另一个命令连接则可以工作。这是我发现的唯一情况，其中 + ， [，] 或 ^ [tab] 可能会失败。

Every one of the other hacks can fail stand-alone in a similar situation. For example, REM^[tab]\..\test.bat fails stand-alone, but works if concatenated with another command. This is the only type of situation I've found where +, [, ], or ^[tab] can fail.

在某些情况下，某些情况

There are additional cases where some of the other hacks can fail.

集合C中的任何字符（ ^ [space] ， ^，， ^; ， ^ = ）在文件名中有效如果存在 remC.bat ，则可以独立失败。例如，以下独立失败：

Any character in the set C (^[space], ^,, ^;, ^=) that are valid in file names can fail stand-alone if remC.bat exists. For example, the following fails stand-alone:

rem^  Fails if "rem .bat" exists

但是，当与另一个命令连接时，它们都是安全的：

Yet they are all safe when concatenated with another command:

echo OK&rem^  This is safe
rem^  This is safe &echo OK

临时更新

Temporary Update

以上某些错误。正在 http：// www进行调查.dostips.com / forum / viewtopic.php？f = 3& t = 6895& p = 44813＃p44813 。

我相信以下是保证在所有情况下都能正常工作的最简单形式（不考虑无效的％扩展）

I believe the following are the simplest forms that are guaranteed to work in all cases (disregarding invalid % expansion)

REM: At least one space (or other token delimiter) must be after :
REM\ At least one space (or other token delimiter) must be after \
REM/ At least one space (or other token delimiter) must be after /
REM^[tab] At lease one space (or other token delimiter) must be after [tab]

但是在尘埃落定之前，我不会更正先前的信息

But I won't correct the earlier info until the dust has settled

结束临时更新

End Temporary Update

我最喜欢的使用内联注释的方法是使用不可能的变量。只有动态伪变量的名称中可以包含 = ，并且任何变量名称都不能包含两个 = 。所以我喜欢使用％=注释在这里=％。这种形式的优点在于，只要注释中不包含％或：。甚至可以在括号内的代码块中安全地使用它。

My favorite way to use inline comments is to use impossible variables. Only dynamic pseudo variables can contain = in a name, and no variable name can ever contain two =. So I like to use %= Remark goes here =%. The beauty of this form is it can be used pretty much anywhere with impunity, as long as the comment does not contain % or :. It can even be used safely within parenthesized blocks of code.

for %%F in (*) do (
   %= Comment within code block     =%
   %= 2nd comment within code block =%
   FINDSTR /B %=Must match beginning of line=%  "string" %= Search string =%  "%%F" %= File to search =%
)

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