Unix Command Internals

But what if you do care?

ls is a little tricky
When it runs, it makes an fstat call on its standard output
- Among other things, this tells it whether stdout is a file or a terminal
If it's a terminal, it enables the column-formatting and color options
If not, it doesn't
You can override this behavior with explicit command-line flags:
- ls -1 (single column)
- ls -C (multiple columns)
- ls --color=never
- ls --color=always