What Is Bash? (And Why Claude Code Keeps Asking Permission)

Bash is the default text-based command shell on most Mac and Linux computers. It’s the program that reads what you type in a terminal window and runs it — copying files, installing software, starting servers, anything you can do without clicking.

Why you’ve heard the word

If you use Claude Code or any other AI coding tool, you’ve seen permission prompts that say things like “Allow Bash command: rm file.txt?” That’s the AI asking permission to run a shell command on your behalf. The shell it’s using is bash (or its close cousin zsh, which is the modern default on macOS but is bash-compatible).

How it relates to other terms

• Bash is a kind of CLI — a command-line interface, the opposite of a GUI (windows and buttons).
• The terminal is the window you type into. Bash is the program running inside that window interpreting what you type.
• A bash script is just a text file full of commands you’d normally type one at a time. You run it once and it executes the whole list.

When AI asks permission to run bash

Read the actual command before you approve. Most are harmless (ls, cat, git status). A few can delete files (rm), modify protected folders (sudo), or change network settings. The approval-gate pattern is what keeps AI tools from running anything destructive without you saying yes first.

Where to learn more

The GNU Bash Reference Manual is the official documentation. For a friendlier intro, search for “bash for beginners” on YouTube — thirty minutes is enough to feel comfortable approving most prompts.

Related

See CLI, GUI, and Claude Code.