Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. First released in 1989, it has been used as the default login shell for most Linux distributions. Bash was one of the first programs Linus Torvalds ported to Linux, alongside GCC.

Bash shell is now more than 30 years old, and still going pretty good. It was first released on June 8, 1989; 33 years ago ( at the time of 2022 )

A version of bash is also there for Windows via Windows Subsystem for Linux. It is also the default user shell in Solaris 11. Bash is a default shell in most Linux distributions. Bash was also the default shell in all versions of Apple macOS prior to the 2019 release of macOS Catalina, which changed the default shell to zsh, although Bash remains available as an alternative shell.

A shell is nothing but a command interpreter, it scans what the user has typed and runs the command associated with it. A terminal window is a software that allows you to access the shell. 

Shell also allows users to pack or use the commands in the file called Shell Script. 

The Bourne shell is a shell command-line interpreter for computer operating systems. The Bourne shell was the default shell for Version 7 Unix. Unix-like systems continue to have /bin/sh—which will be the Bourne shell, or a symbolic link or hard link to a compatible shell—even when other shells are used by most users. 

The Bourne shell was an upgraded version of the shell, was interactive with the added functionality of foreground and background task executions, pipes and redirection were added to it. It was also optimized or good at handling the loops. 

Bash shell is a replacement for the Bourne shell, it brings standard and amazing features. 

Bash is a very old shell, it has a great user base, and it is a user-friendly and stable shell. Now there are also some other alternatives to bash which provides some better features than bash like ZSH & Fish but still bash is a dominant shell. 

Another reason is that since the bash is in the market for a long time everyone has used it. You get bash as the shell in UNIX, Linux so if you are switching it is easy to switch because of the familiarity & you already know the bash, so there is no learning curve there. 

As it is available for a long time the community support for it has grown so much, that if you are having any issue related to it, you are going definitely going to find a solution for that. And the community support for bash is pretty huge as compared to the other shells. 

Bash has great documentation. 

If you are using a Linux or Unix system. 

echo is a command which gives output to the screen & SHELL is a system variable that shows the default shell of the user. 

Bash is a shell replacement for the Bourne shell. First released in 1989, it has been used as the default login shell for most Linux distributions. Bash was one of the first programs Linus Torvalds ported to Linux. Bash brings standard and amazing features. You get bash as the shell in UNIX, Linux so if you are switching it is easy to switch because of the familiarity & you already know the bash, so there is no learning curve there. 

Why bash is considered better than the rest of the shell?