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Erlang Run-Time System Application (ERTS)
User's Guide
Version 5.9.2

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Chapters

- Match specifications in Erlang
  - Top of chapter
  - Grammar
  - Function descriptions
  - Variables and literals
  - Execution of the match
  - Differences between match specifications in ETS and tracing
  - Examples
- How to interpret the Erlang crash dumps
  - Top of chapter
  - General information
  - Memory information
  - Internal table information
  - Allocated areas
  - Allocator
  - Process information
  - Port information
  - ETS tables
  - Timers
  - Distribution information
  - Loaded module information
  - Fun information
  - Process Data
  - Atoms
  - Disclaimer
- How to implement an alternative carrier for the Erlang distribution
  - Top of chapter
  - Introduction
  - The driver
  - Putting it all together
- The Abstract Format
  - Top of chapter
  - Module declarations and forms
  - Atomic literals
  - Patterns
  - Expressions
  - Clauses
  - Guards
  - The abstract format after preprocessing
- tty - A command line interface
  - Top of chapter
  - Normal Mode
  - Shell Break Mode
- How to implement a driver
  - Top of chapter
  - Introduction
  - Sample driver
  - Compiling and linking the sample driver
  - Calling a driver as a port in Erlang
  - Sample asynchronous driver
  - An asynchronous driver using driver_async
- Inet configuration
  - Top of chapter
  - Introduction
  - Configuration Data
  - User Configuration Example
- External Term Format
  - Top of chapter
  - Introduction
  - Distribution header
  - ATOM_CACHE_REF
  - SMALL_INTEGER_EXT
  - INTEGER_EXT
  - FLOAT_EXT
  - ATOM_EXT
  - REFERENCE_EXT
  - PORT_EXT
  - PID_EXT
  - SMALL_TUPLE_EXT
  - LARGE_TUPLE_EXT
  - NIL_EXT
  - STRING_EXT
  - LIST_EXT
  - BINARY_EXT
  - SMALL_BIG_EXT
  - LARGE_BIG_EXT
  - NEW_REFERENCE_EXT
  - SMALL_ATOM_EXT
  - FUN_EXT
  - NEW_FUN_EXT
  - EXPORT_EXT
  - BIT_BINARY_EXT
  - NEW_FLOAT_EXT
- Distribution Protocol
  - Top of chapter
  - EPMD Protocol
  - Handshake
  - Protocol between connected nodes
  - New Ctrlmessages for distrvsn = 1 (OTP R4)
  - New Ctrlmessages for distrvsn = 2
  - New Ctrlmessages for distrvsn = 3 (OTP R5C)
  - New Ctrlmessages for distrvsn = 4 (OTP R6)

# 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.

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

Table 5.1: tty text editing

### 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