View Source werl

The Erlang Emulator on Windows



Since Erlang/OTP 26 the werl.exe command is now only a link to erl.exe as the normal Erlang shell has been updated to work on both Unix and Windows in the same way.

The text below is kept for systems that have yet to upgrade to Erlang/OTP 26

On Windows, the preferred way to start the Erlang system for interactive use is as follows:

werl <arguments>

This starts Erlang in its own window, with fully functioning command-line editing and scrollbars. All flags except -oldshell work as they do for erl(1).

  • To copy text to the clipboard, use Ctrl-C.
  • To paste text, use Ctrl-V.
  • To interrupt the runtime system or the shell process (depending on what has been specified with system flag +B), use Ctrl-Break.

In cases where you want to redirect standard input and/or standard output or use Erlang in a pipeline, werl is not suitable, and the erl program is to be used instead.

The werl window is in many ways modeled after the xterm window present on other platforms, as the xterm model fits well with line-oriented command-based interaction. This means that selecting text is line-oriented rather than rectangle-oriented.

  • To select text in the werl window, press and hold the left mouse button and drag the mouse over the text you want to select. If the selection crosses line boundaries, the selected text consists of complete lines where applicable (just like in a word processor).
  • To select more text than fits in the window, start by selecting a small part in the beginning of the text you want, then use the scrollbar to view the end of the desired selection, point to it, and press the right mouse button. The whole area between your first selection and the point where you right-clicked is included in the selection.
  • To copy the selected text to the clipboard, either use Ctrl-C, use the menu, or press the copy button in the toolbar.

Pasted text is inserted at the current prompt position and is interpreted by Erlang as usual keyboard input.

  • To retrieve previous command lines, press the Up arrow or use Ctrl-P.

A drop-down box in the toolbar contains the command history. Selecting a command in the drop-down box inserts the command at the prompt, as if you used the keyboard to retrieve the command.

  • To stop the Erlang emulator, close the werl window.