| <!-- $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $ --> |
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| <TITLE>LUA man page</TITLE> |
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| |
| <H2>NAME</H2> |
| lua - Lua interpreter |
| <H2>SYNOPSIS</H2> |
| <B>lua</B> |
| [ |
| <I>options</I> |
| ] |
| [ |
| <I>script</I> |
| [ |
| <I>args</I> |
| ] |
| ] |
| <H2>DESCRIPTION</H2> |
| <B>lua</B> |
| is the stand-alone Lua interpreter. |
| It loads and executes Lua programs, |
| either in textual source form or |
| in precompiled binary form. |
| (Precompiled binaries are output by |
| <B>luac</B>, |
| the Lua compiler.) |
| <B>lua</B> |
| can be used as a batch interpreter and also interactively. |
| <P> |
| The given |
| <I>options</I> |
| (see below) |
| are executed and then |
| the Lua program in file |
| <I>script</I> |
| is loaded and executed. |
| The given |
| <I>args</I> |
| are available to |
| <I>script</I> |
| as strings in a global table named |
| <B>arg</B>. |
| If these arguments contain spaces or other characters special to the shell, |
| then they should be quoted |
| (but note that the quotes will be removed by the shell). |
| The arguments in |
| <B>arg</B> |
| start at 0, |
| which contains the string |
| '<I>script</I>'. |
| The index of the last argument is stored in |
| <B>arg.n</B>. |
| The arguments given in the command line before |
| <I>script</I>, |
| including the name of the interpreter, |
| are available in negative indices in |
| <B>arg</B>. |
| <P> |
| At the very start, |
| before even handling the command line, |
| <B>lua</B> |
| executes the contents of the environment variable |
| <B>LUA_INIT</B>, |
| if it is defined. |
| If the value of |
| <B>LUA_INIT</B> |
| is of the form |
| '@<I>filename</I>', |
| then |
| <I>filename</I> |
| is executed. |
| Otherwise, the string is assumed to be a Lua statement and is executed. |
| <P> |
| Options start with |
| <B>'-'</B> |
| and are described below. |
| You can use |
| <B>'--'</B> |
| to signal the end of options. |
| <P> |
| If no arguments are given, |
| then |
| <B>"-v -i"</B> |
| is assumed when the standard input is a terminal; |
| otherwise, |
| <B>"-"</B> |
| is assumed. |
| <P> |
| In interactive mode, |
| <B>lua</B> |
| prompts the user, |
| reads lines from the standard input, |
| and executes them as they are read. |
| If a line does not contain a complete statement, |
| then a secondary prompt is displayed and |
| lines are read until a complete statement is formed or |
| a syntax error is found. |
| So, one way to interrupt the reading of an incomplete statement is |
| to force a syntax error: |
| adding a |
| <B>';'</B> |
| in the middle of a statement is a sure way of forcing a syntax error |
| (except inside multiline strings and comments; these must be closed explicitly). |
| If a line starts with |
| <B>'='</B>, |
| then |
| <B>lua</B> |
| displays the values of all the expressions in the remainder of the |
| line. The expressions must be separated by commas. |
| The primary prompt is the value of the global variable |
| <B>_PROMPT</B>, |
| if this value is a string; |
| otherwise, the default prompt is used. |
| Similarly, the secondary prompt is the value of the global variable |
| <B>_PROMPT2</B>. |
| So, |
| to change the prompts, |
| set the corresponding variable to a string of your choice. |
| You can do that after calling the interpreter |
| or on the command line |
| (but in this case you have to be careful with quotes |
| if the prompt string contains a space; otherwise you may confuse the shell.) |
| The default prompts are "> " and ">> ". |
| <H2>OPTIONS</H2> |
| <P> |
| <B>-</B> |
| load and execute the standard input as a file, |
| that is, |
| not interactively, |
| even when the standard input is a terminal. |
| <P> |
| <B>-e </B><I>stat</I> |
| execute statement |
| <I>stat</I>. |
| You need to quote |
| <I>stat </I> |
| if it contains spaces, quotes, |
| or other characters special to the shell. |
| <P> |
| <B>-i</B> |
| enter interactive mode after |
| <I>script</I> |
| is executed. |
| <P> |
| <B>-l </B><I>name</I> |
| call |
| <B>require</B>('<I>name</I>') |
| before executing |
| <I>script</I>. |
| Typically used to load libraries. |
| <P> |
| <B>-v</B> |
| show version information. |
| <H2>SEE ALSO</H2> |
| <B>luac</B>(1) |
| <BR> |
| <A HREF="http://www.lua.org/">http://www.lua.org/</A> |
| <H2>DIAGNOSTICS</H2> |
| Error messages should be self explanatory. |
| <H2>AUTHORS</H2> |
| R. Ierusalimschy, |
| L. H. de Figueiredo, |
| and |
| W. Celes |
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