How to Add Comments in a Batch or CMD File

A batch file or CMD is a text file that contains a series of commands that can be executed by the Windows operating system.

Batch files, also known as CMD scripts, are an essential tool in the world of software development. Batch files can be used to perform various tasks, such as running programs, copying files, or changing system settings. Batch files usually have an extension .bat or .cmd.

One of the important things in creating a batch file is adding comments. A comment is a line of text that is not executed by the operating system but only serves as a note or explanation for the creator or reader of the batch file.

Comments can be used to explain what a line of code does or to document the function of a batch file. In addition, comments can also help you understand the purpose and logic of batch files, as well as make it easier for you to modify or repair batch files in the future.

How to Add a Comment

In batch language (.cmd), there are three common ways to comment out or disable code by using “REM” marks, “::” and “%==%.” Each method has uses and uniqueness that need to be understood to be used effectively in batch file development.

1] Using the “REM” Mark

 “REM” stands for “remark” and is an internal command found inside the Windows Command Processor Command Prompt, which makes it possible to include comments inside batch programs.

A comment is a line of text that is not executed by the operating system but only serves as a note or explanation for the creator or reader of the batch program. Comments can help you understand the purpose and logic of a batch program, as well as make it easier for you to modify or improve the batch program in the future.

Comments are essential in maintaining readability and understanding of your code. You can comment out various parts of a batch file by using the “REM” mark, like the example below:

REM This is a comment 
REM Comments Will Not Be Executed by the Operating System

You can also use REM marks to temporarily disable a command without removing it from the batch program. Example:

REM del C:\Windows\System32\file.txt

The above command should delete the file named file.txt from the C:WindowsSystem32 folder, but because it begins with a break mark, it will not be executed. This is useful if you want to test or debug your batch program without changing the results.

2] Using the “::” Sign

 “::” is a shorter alternative to adding comments to code. However, this only works when placed at the beginning of the line. While not an official command, it is commonly used and more aesthetically pleasing in code.

:: This is also a comment

The advantage of using colons is that you don’t have to add spaces after them, so your comments can be shorter and neater. However, the downside of using colons is that you can’t use special characters like &, |, <, >, or ^ in your comments because those characters have special functions in batch program syntax.

3] Using the sign “%==%”

%= =% is the most flexible way to add comments. You can use this method to add comments to lines of code, to command parameters, or variables.

For example, the following code will add the comment “This is a comment for the line of code” to the first line of code:

set <strong>“var=3”</strong> %= This is a comment on the same line=%

 “%==%” is a less common way to disable parts of code. This allows you to quickly disable several lines of code and easily reactivate them. However, it may not be as common as other options and is less familiar to many developers.

The difference between “REM”, “::”, and “%==%”

Here is a table summarizing the differences between REM, ::, and %==%:

•  “REM” is the official command for comments in batch files.
•  “::” is a shorter alternative, but it only works at the beginning of the line.
•  “%===%” is a less common way to quickly disable code.

In general, REM is the most common and compatible way to add comments to a batch file. :: is a shorter and more efficient way, but it is not compatible with all versions of CMD. %= =% is the most flexible way, but it is only available on Windows 10 and higher.

When to use a particular method?

• Use “REM” for clear comments and explanations that require an official introduction.
• Use “::” for short comments that clarify the code at the beginning of the line.
• Use “%===%” to disable longer sections of code that need to be temporarily disabled.

Conclusion

Ultimately, your choice between “REM,” “::,” and “%==%” depends on personal preferences and project demands. “REM” is the official choice for comments, “::” is a more concise option commonly used at the beginning of a line, and “%==%” is a less common way to disable code. Understand the differences and use the method that best suits your writing style and development needs