Which shell is commonly used as the default in Linux?

Bash, or the Bourne Again SHell, is the shell commonly used as the default in most Linux distributions. It serves as an enhanced version of the original Bourne shell (sh) and provides more features, including command-line editing, improved scripting capabilities, and a wider range of built-in functions and variables. Its popularity stems from its robust features and its compatibility with many scripts written for the Bourne shell, making it the preferred choice for both users and developers.

While other shells like fish and zsh offer unique features and functionalities—fish focuses on user-friendliness and offers suggestions, while zsh features advanced customization options—they are not as widely adopted as bash. Sh is an older shell that is often used for scripting but generally lacks the extended features available in bash, which has become the standard across various distributions. This widespread adoption and the extensive support make bash the default choice in the majority of Linux environments.