bc:tldr:22321

This command is utilizing the "echo" command to send a mathematical expression '${5 - 3}' as input to the "bc" command.

Here's a breakdown of what each component does:

• echo: The "echo" command is used to display a line of text or expressions as output.
• ${5 - 3}: Inside single quotes (' '), this expression represents the mathematical subtraction operation of 5 minus 3.
• |: This vertical bar is a pipe symbol used to redirect the output of the previous command (echo) to become the input of the next command (bc).
• bc: The "bc" command stands for "Basic Calculator" and is used for performing mathematical calculations in the command-line interface (CLI). It reads the input from the previous command and evaluates the expression.

So when the command is executed, the value of 5 - 3 is sent to bc for evaluation, and bc will compute the result of the subtraction and display it as output.