BASH Programming

How to Create Multiline Comments in Bash

Bash is a popular shell used in Unix-based operating systems as it provides a range of features to help users automate tasks and manage system resources efficiently. One of the essential aspects of Bash programming is commenting on the code. In this article, we will discuss ways to create multiline comments in Bash and provide examples for each method.

Create Multiline Comments in Bash

In Bash, you can create multiline comments using:

Method 1: Create Multiline Comments Using the Hash Symbol (#)

The most common way to create a comment in Bash is to use the hash symbol (#). To create a multiline comment, you can use multiple hash symbols at the beginning of each line, here is an example:

# This is a multiline comment
# That spans across multiple lines.
# We use hash symbols to begin each line.
ls

In the above code, we just used the # symbol to add comments which is the conventional way to add comments in a bash program, next there is a ls command that just list the contents of the current directory:

Method 2: Create Multiline Comments Using Here Documents

Here documents are another way to create multiline comments in Bash. Here documents allow you to specify a block of text and pass it as input to a command. To create a multiline comment using here documents, you can use the following syntax:

: <<'END_COMMENT'
This is a multiline comment
that spans across multiple lines.
We use here documents to create this comment.
END_COMMENT
ls

In this example, we use a colon followed by the << symbol to start the here document and We then specify a delimiter (END_COMMENT in this case) to indicate the end of the comment. Everything between the delimiters is considered a comment, the code just lists all the data present in the current directory:

Method 3: Create Multiline Comments Using a Function

You can also create a function that contains your multiline comment in Bash. To do this, you can define a function that does nothing and add your comment as a string inside the function. Here is an example:

# Define the function
function multiline_comment {
    : "
    This is a multiline comment
    that spans across multiple lines.
    We use a function to create this comment.
    "

}
# Call the function to create the comment
multiline_comment

ls

In the above example, we define a function called “multiline_comment” that contains our comment as a string. We then call the function to create the comment and afterwards used the ls command to list all the contents of the same directory:

Conclusion

Commenting code is an essential aspect of Bash programming. It helps developers to explain their code and make it easier for others to understand. In this article, we discussed three different ways to create multiline comments in Bash. These methods include using the hash symbol (#), here documents, and a function. By using these methods, you can create well-documented Bash code that is easy to read and maintain.

About the author

Aaliyan Javaid

I am an electrical engineer and a technical blogger. My keen interest in embedded systems has led me to write and share my knowledge about them.