Command substitution

So far, we have seen how to declare variables. These variables can hold integers, strings, arrays, or floats, as we have seen, but this is not everything.

A command substitution means storing the output of a command execution in a variable.

As you might know, the pwd command prints the current working directory. So, we will see how to store its value in a variable.

There are two ways to perform a command substitution:

• Using the backtick character (')
• Using the dollar sign format, like this: $()

Using the first method, we just surround the command between two backticks:

#!/bin/bash 
cur_dir='pwd'
echo $cur_dir 

And the second way is written as follows:

#!/bin/bash 
cur_dir=$(pwd) 
echo $cur_dir 

The output coming from commands can be further processed and actions can be made based on that output.