In Bash, it’s common to run Linux commands and capture their output for later use in a script. You can assign the output of a command to a variable by using command substitution, which is a feature of Bash that allows you to execute a command and replace it with its output. There are two ways to assign output to a variable and those are:

• Through Command Substitution
• Through Backticks

1: How to use Command Substitution to Assign Output of a Linux Command to a Variable

One way to assign the output of a Linux command to a variable in Bash is to use command substitution with the $() syntax and here is the complete syntax for it:

Here’s an example has been done which save the hostname command output in a variable using the syntax given above:

In this example, we used the hostname command to get the name of the current host, and then assigned the output to the find_hostname variable using command substitution. Finally, we printed the value of find_hostname variable using the echo command:

2: How to use Backticks to Assign Output of a Linux Command to a Variable

Another way to assign the output of a Linux command to a variable is to use backticks (`) instead of parentheses and below is the syntax for it:

To further explain how to use this method I have given an example bash code that just reads the path or current directory.

In this example, we used the pwd command to get the current working directory, and then assigned the output to the current_dir variable using backticks. Finally, we printed the value of the current_dir variable using the echo command:

Conclusion

Assigning the output of a Linux command to a variable is a common task in Bash scripting and can be accomplished using command substitution with either parentheses or backticks. By using these techniques, you can capture the output of a command and use it in your scripts to perform various tasks. You can use any of these three methods to assign the output of a Linux command to a variable in Bash, depending on your specific needs and preferences.