Комментарий в командной строке windows

The command you’re looking for is rem, short for «remark».

There is also a shorthand version :: that some people use, and this sort of looks like # if you squint a bit and look at it sideways. I originally preferred that variant since I’m a bash-aholic and I’m still trying to forget the painful days of BASIC

Unfortunately, there are situations where :: stuffs up the command line processor (such as within complex if or for statements) so I generally use rem nowadays. In any case, it’s a hack, suborning the label infrastructure to make it look like a comment when it really isn’t. For example, try replacing rem with :: in the following example and see how it works out:

if 1==1 (
    rem comment line 1
    echo 1 equals 1
    rem comment line 2
)

You should also keep in mind that rem is a command, so you can’t just bang it at the end of a line like the # in bash. It has to go where a command would go. For example, the first line below outputs all hello rem a comment but the second outputs the single word hello:

echo hello rem a comment.
echo hello& rem a comment.

The second is two separate commands separated by &, and with no spaces before the & because echo will output those as well. That’s not necessarily important for screen output but, if you’re redirecting to a file, it may:

echo hello >file          - includes the space.
echo hello>file           - no space.

Rem (abbreviation of remark) is a command (internal) found inside the Windows Command Processor Command Prompt, that allows for inclusion of comments inside batch programs. Comments are supported by most Programming languages usually via special syntax that is associated to them. Ex. Python using pound sign/hashtag ( # ) to denote a inline comment. Rem command is for inline comments, therefore the comment would only be valid till the end of the current line (or first occurrence of CRLF) Though multiline comments can be created using multiple Rem command on separate lines. In this article we will take a look at the Rem command, and would get to know about various uses for it. 

Description of the Command :

Records comments (remarks) in a batch file or CONFIG.SYS.

REM [comment] 

*The above output can be obtained by executing rem /? command in the commandline

Using the Command : Comments are generally used to add more intel to the code. It helps in providing an insight to what the creator of the code, was thinking while writing it. It is also useful for providing some pointers or addendum related to the code. Comments overall help in reducing the complexity of the code, by being a sort of human-readable form of code. They also help to guide readers, who are unaware of the language. 
For Example, let’s take a look at the following code snippet:

@echo off

echo %~f0
echo %~t0

To someone who has never seen the aforementioned syntax, the code may be quite cryptic at first. But if comments are added to the code:

REM Used to disable echo of command entry and current working directory
@echo off

REM Displaying the full path (absolute Path) of this file
echo %~f0

REM Displaying the timestamp of creation of this file
echo %~t0

The code becomes clear on its functionality, and one can easily guide through its workings. 

Creating Inline Comments : 
Inline comments can be created by using the REM command at the beginning of the line and then typing in the comment. 
For example,

REM This code will display hello world
echo hello world!

Inline comments could also be added to the end of the line (preceded by some code) by using the & REM construct. 
For example,

echo Hello World! & REM This code will display hello world

Creating Multiline Comments : 
Multiline comments can be created by using multiple rem commands, that span several lines. 
For example,

REM This code will tell the current time
REM The resolution of the time will be until milliseconds
REM The time will be based on the current timezone
echo | time

Note – 
Comment creation exists through various other means as well. Ex. There exists other types of ~comments which allows for comments in between a statement. But they are not the documented way of commenting code, and exists due to workaround of other commands/syntaxs. Also, those are outside the scope of this article.

Last Updated :
04 Apr, 2023

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