1
0
mirror of https://github.com/elua/elua.git synced 2025-01-08 20:56:17 +08:00
elua/docs/the_elua_shell.txt
2008-11-01 20:39:50 +00:00

74 lines
3.0 KiB
Plaintext

(NOTE: view this file with a monospaced font)
The eLua shell
================================================================================
After you burn eLua to your board and you connect the board to your terminal
emulator running on the PC, you'll be greeted with the eLua shell prompt, which
allows you to:
- run 'lua' as you would run it from the Linux or Windows command prompt
- upload a Lua source file via XMODEM and execute in on board
- query the eLua version
- get help on shell usage
To enable the shell, define BUILD_SHELL in your build.h file, and also
BUILD_XMODEM if you want to use the "recv" command (see below). See
docs/elua_components.txt for more details about enabling the shell.
You'll need to configure your terminal emulation program to connect to your eLua
board. These are the parameters you'll need to set for your serial connection:
- speed 115200, 8N1 (8 data bits, no parity, one stop bit)
- no flow control
- newline handling (if available): CR on receive, CR+LF on send
After you setup your terminal program, press the RESET button on the bord.
When you see the "eLua# " prompt, just enter "help" to see the on-line shell
help:
eLua# help
Shell commands:
help - print this help
lua [args] - run Lua with the given arguments
recv - receive a file (XMODEM) and execute it
ver - print eLua version
exit - exit from this shelll
More details about some of the shell commands are presented below.
The "recv" command
================================================================================
To use this, your eLua target image must be built with support for XMODEM (see
docs/elua_components.txt for details). Also, your terminal emulation program must
support sending files via the XMODEM protocol. Both XMODEM with checksum (the
original version) and XMODEM with CRC are supported, but only XMODEM with 128
byte packets is allowed (XMODEM with 1K packets won't work).
To use this feature, enter "recv" at the shell prompt. eLua will respond with
"Waiting for file ...". At this point you can send the file to the eLua board
via XMODEM. eLua will receive and execute the file. Don't worry when you see 'C'
characters suddenly appearing on your terminal after you enter this command,
this is how the XMODEM transfer is initiated.
The "lua" command
================================================================================
This allows you to start the Lua interpreter with command line parameters, just
as you would do from a Linux or Windows command prompt. This command has some
restrictions:
- the command line can't be longer than 50 chars
- character escaping is not implemented. For example, the next command won't work
because of the \' escape sequences:
eLua# lua -e 'print(\'Hello, World!\')' -i
Press CTRL+Z to exit Lua
lua: (command line):1: unexpected symbol near '\'
However, if you use both '' and "" for string quoting, it will work:
eLua# lua -e 'print("Hello, World")' -i
Press CTRL+Z to exit Lua
Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio
Hello,World
>