Bash the Hash! - a Symbolic Feature of Bash Comment

Hashing is the main piece of the solution in a Bash-coded puzzle. The hash (#) symbol put on the initial point of any line resembles an explanatory statement of any complicated program in Bash script. In this article, I will explain the term ‘Bash the hash’ with its practical execution. Let’s explore!

Table of Contents

Key Takeaways

Learning what is hashing in Bash script.
Getting ideas about the execution of Bash hashing.

What is Bash Hashing?

Bash hashing is the symbolic formula for marking out single-line comments & multiple-line comments in Bash script. With some exceptions, putting a hash(#) symbol before any line is enough to call it a Bash comment. Apparently, it makes the compiler bound to skip the hashed line from the script execution. Thus, hashing turns a line into a non-executable code.

Execution of Bash Hashing

In the following section, you’ll get a visual concept of what happens to a hashed line during any script execution. So, move on to the steps below:

Steps to Follow >

➊ Open your Ubuntu Terminal.

➋ To open a script in the nano text editor, write the following command:

nano hash.sh

EXPLANATION

nano: A text editor.
hash.sh: This is a script that you can name by any of your choices. Here, I have named the script by ‘hash.sh’.

➌Then, write the following script in the nano editor:

Script (hash.sh) >

#!/bin/bash

#echo "This is a comment."

echo "This is not a comment. So, it is printed."

EXPLANATION

Here, #! /bin/bash: ‘#!’, is called shebang. Now, #echo “This is a comment.” indicates a comment as the line starts with a hash symbol. Lastly, echo “This is not a comment. So, it is printed.” dictates a command that will be executed.

➍ Then, press CTRL+S to save the file & press CTRL+X to exit the nano editor & back to the terminal.

➎ Afterward, use the following command to make the script executable:

chmod u+x hash.sh

EXPLANATION

chmod: Changes the permission of the files and directories.
u+x: It’s an argument that is used to add the executable permission for the user.
hash.sh: The file which you want to make executable. Here, I have used a file named ‘hash.sh’.

Adding executable permission to the script

➏ Finally, run the script by the following command:

./hash.sh

From the above image, you can see that when I ran the script ‘hash.sh’, it displayed only one line which was written inside the echo command & there was no hash symbol before this line on the script. On the contrary, the line that started with a hash symbol did not execute as it refers only to a statement.

Conclusion

Bash hashing is nothing but a commenting-out feature of a Bash script. Though this is not executable, it participates in making the script more readable and accessible.

People Also Ask

Can I comment out any single-line in Bash without using the hash(#) symbol?

No, to comment a single-line out, it is mandatory to use a hash(#) symbol at the beginning of a line in Bash script.

Can I use the hash(#) symbol for any purpose other than commenting out in Bash?

Yes, you can use the hash symbol for other purposes too. For example, when you use the hash symbol in a variable expansion like ‘${#variable}’, it indicates the length of the variable.

Can the hash(#) symbol cause any unexpected issue in Bash scripting?

If the hash symbol within a string is not properly mentioned, then it may cause a syntax error.

Is there any way to comment out in Bash ignoring the hash(#) symbol?

Yes, you can apply multiple-line commenting in Bash scripting to avoid the hash symbol.

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