Like any other scripting language, Zsh allows us to include the comments to create and document the maintainable scripts. Using comments, we can provide explanations, documentations, and remarks within the code blocks.
Join us in this tutorial where we look at the role and usage of comments in the scripting language using Zsh.
Comments and Why We Need Them
Let us start at the basics and discuss what comments are, what role they play, and why we need them in a scripting language such as Zsh.
Comments are explanatory remarks or annotations that we add to a script or source code. Comments are ignored by the interpreter which make them very useful in disabling the code blocks or just adding notes to the code.
Comments are an integral part of any scripting language, and Zsh is no exception. If you are still wondering why you need comments, the following is a list good reasons:
- Comments serve as documentation for the code which makes it easier for you and others to understand the purpose and functionality.
- Well-placed comments enhance the readability of the code which makes it more accessible for debugging and maintenance.
- Comments can enable you to communicate with other developers such as rationale behind code sections.
- Comments can act as reminders which help you remember the purpose of specific code blocks.
Zsh Comment Syntax
In Zsh, we can add the comments using the “#” symbol. The “#” symbol denotes the start of a comment until the end of the line. Hence, everything following the pound symbol on the same line is treated as a comment and is ignored by the shell.
Single-Line Comments
Single-line comments are the most common type of comments in Python. You can think of them as a way to add a remark about a specific line of code or block.
The following shows the basic syntax of single-line comments:
# This is a single-line comment
echo "Hi, there!" # Also a single-line comment
Multi-Line Comments
While Zsh doesn’t provide a built-in syntax for multi-line comments like some other languages, we can achieve the multi-line comments using a workaround with heredocs.
We can use the heredocs to embed the text within the script without actually executing it. This works very similar to multi-line comments.
The following shows a multi-line comment using Zsh heredocs:
<<COMMENT
This is a multi-line comment.
another
and another
COMMENT
echo "Hi, there!"
In this example, everything between <<COMMENT and COMMENT blocks is treated as a comment and is ignored by the shell.
Example Usage
The following code block demonstrates how to use the comments to document the functionality of a given code block:
calculate_square() {
local number="$1" # Input number
local square=$((number * number)) # Calculate the square
echo "The square of $number is $square"
}
We can also use the comments to explain a more complex logic as follows:
if [[ -r "$file" ]]; then
# File is readable
# Proceed with further processing
else
# File is not readable
# Display an error message
echo "Error: The file is not readable."
fi
This can serve an incredible role in helping the other devs understand your code much more quickly.
FAQs
When should I use the comments?
Use comments for clarity, explanations, and documentation in your code, especially when it’s complex or not immediately understandable.
Can I nest the comments within comments?
No, nesting comments within comments is not allowed in programming languages including Zsh.
Should I remove the comments before deploying the code?
Keep the comments for understanding during development, but it’s common to remove them in production to improve the file size and runtime performance.
Conclusion
In this tutorial, we discussed everything you need to know to become an expert in the usage and formatting of comments in Zsh scripts.
