What is the UNIX Shell (Bash)?
The UNIX shell is a program to interface with the lowest level of UNIX-based operating systems (i.e., the kernel). If you are running any Mac OS or Linux Distribution, you are using a UNIX-based or Unix-like operating system. UNIX-based operating systems have two main parts: the kernel and the utilities. The kernel is the program managing and allocating the resources of the computer hardware (i.e., the Central Processing Unit or CPU, the Random Access Memory or RAM, and devices like the mouse, speaker, etc). It is a software layer facilitating the control of the computer hardware. The utilities are a set of commands to interface with the kernel. For instance, if you type pwd in your terminal, the kernel will load a program called pwd into the RAM, read the program instructions, and display the output, in this case, the current working directory path.
The so-called shell, also happens to be a UNIX utility program. It has a dual identity: as a user interface to the UNIX utilities, and as a programming language facilitating the usage and combination of the UNIX utilities. When you open the terminal, the shell program is loaded into the computer memory. When you type commands in the terminal, the shell reads the commands and converts them into a format that is readable by the kernel to be executed. It provides an interactive instance to start programs, manage files, and processes running in the computer.
Recommended path for learing
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Introductory article: Introduction to the UNIX Shell (Bash)
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74 minutes introductory video: Beginner’s Guide to the Bash Terminal
Video courses
- Bash Script with Practical Examples - Full Course
- Linux Command Line Full course: Beginners to Advance. Bash Command Line Tutorials