What provides autocompletion? Shell or emulator?

Question

I have been using Linux for some time now. Now, I have question about auto-completion of commands and directories in a terminal window.

When I press a tab key the terminal auto-completes or gives choice. Is this auto-completion provided by the shell or is it a feature of the emulator.

Also, if its provided by the terminal, how does a terminal provide it so transparently.

Answer 1

The shell provides the auto-completion. It's not a separate script but built into the shell itself -- for standard file completion.

Auto-completion on arguments is built on the programmable completion facility built into bash. See the "Programmable Completion" section of the bash man page.

Some Linux distributions provide the bash_completion package. This is a collection of configuration options which utilize the programmable completion commands in bash.

Answer 2

Auto completion is provided by the shell.
When Tab is pressed, the shell runs a script that decides, based on what you've typed already, what, exactly, needs to be completed. The script then generates a list of possible completions, which may or may not be the list of files in the current directory, or the list of executable files in your $PATH.

Answer 3

the shell provides this. the terminal emulator draws what the shell produces and hands over user input to the shell.