Good article, but I love to pick nits so let be be a nitpicking SOAB.

The shell is a way to interact textually with the computer. The most popularUnix shell is Bash(Bourne Again SHell ). Bash is the default shell on most modern implementations of Unix…

This was never true.

Sh (Bourne Shell) is / was the most popular UNIX shell.
Bash is probably the most used Linux shell, BUT, Linux is not Unix.
Newer was, never will be.
Calling something a UNIX Operating System requires a fairly strict certification. You can’t “implement Unix” as you say unless it IS Unix.

Here is a list of the currently registered “Certified Unix” products alive:

• Apple Inc.: macOS version 10.15 Catalina on Intel-based Mac computers
• IBM Corporation: AIX version 7, at either 7.1 TL5 (or later) or 7.2 TL2 (or later) on systems using CHRP system architecture with POWER™ processors
• Cemprus LLC: DNCP Series running FTX Release 3
• Hewlett Packard Enterprise: HP-UX 11i V3 Release B.11.31 or later on HP Integrity Servers
• Hewlett Packard Enterprise: HP-UX 11i V3 Release B.11.31 or later on HP 9000 Servers with Precision Architecture
• Huawei Technology Co., Ltd: Huawei EulerOS 2.0 on Huawei KunLun Mission Critical Server
• IBM Corporation: AIX 6 Operating System V6.1.2 with SP1 or later on Systems using CHRP system architecture with POWER™ processors and 2, 8 or 128 port async cards
• IBM Corporation: AIX 5L for POWER V5.3 dated 7-2006 or later on Systems using CHRP system architecture with POWER™processors
• IBM Corporation: z/OS V2R1 or later with: z/OS V2R1 or later Security Server and z/OS V2R1 or later C/C++ Compiler on IBM zSeries Processors that support z/OS Version 2 Release 1 or later
• The SCO Group, Inc.: UnixWare ® 7.1.3 and later for single and multiprocessor systems based on IA-32 and compatible processors and conforming to PC architecture
• The SCO Group, Inc.: SCO OpenServer Release 5 and OpenServer Release 6 on Single and Multi-processor Industry Standard Intel architecture platforms