## 5 tty - A command line interface

tty is a simple command line interface program where keystrokes are collected and interpreted. Completed lines are sent to the shell for interpretation. There is a simple history mechanism, which saves previous lines. These can be edited before sending them to the shell. tty is started when Erlang is started with the command:

erl

tty operates in one of two modes:

- normal mode, in which lines of text can be edited and sent to the shell.
- shell break mode, which allows the user to kill the current shell, start multiple shells etc. Shell break mode is started by typing Control G.

### 5.1 Normal Mode

In normal mode keystrokes from the user are collected and interpreted by tty. Most of the emacs line editing commands are supported. The following is a complete list of the supported line editing commands.

Note: The notation C-a means pressing the control key and the letter a simultaneously. M-f means pressing the ESC key followed by the letter f.

tty text editing
Key Sequence | Function
C-a | Beginning of line
C-b | Backward character
M-b | Backward word
C-d | Delete character
M-d | Delete word
C-e | End of line
C-f | Forward character
M-f | Forward word
C-g | Enter shell break mode
C-k | Kill line
C-l | Redraw line
C-n | Fetch next line from the history buffer
C-p | Fetch previous line from the history buffer
C-t | Transpose characters
C-y | Insert previously killed text

### 5.2 Shell Break Mode

tty enters shell break mode when you type Control G. In this mode you can:

- Kill or suspend the current shell
- Connect to a suspended shell
- Start a new shell

erts 5.6.5
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