In this post, the concept of Shell is introduced.

Kernel & Shell

• Hardware includes memory, hard disk, SSD, CPU and other physical things.
• Kernel is a core part of OS. OS directly controls hardware.
• Shell interprets the user’s commands and passes them to the Kernel in a way that the kernel can understand. When you type ‘ls’ in your terminal, Shell interprets the command and passes it to Kernel. Then Kernel controls the hardware to do some tasks. The hardware gives the results for the command to the Kernel and Kernel passes them to Shell. Finally you can see the results of ‘ls’ in your terminal zsh and bash are widely used shell program.