1<!-- $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $ --> 2<HTML> 3<HEAD> 4<TITLE>LUA man page</TITLE> 5<LINK REL="stylesheet" TYPE="text/css" HREF="lua.css"> 6</HEAD> 7 8<BODY BGCOLOR="#FFFFFF"> 9 10<H2>NAME</H2> 11lua - Lua interpreter 12<H2>SYNOPSIS</H2> 13<B>lua</B> 14[ 15<I>options</I> 16] 17[ 18<I>script</I> 19[ 20<I>args</I> 21] 22] 23<H2>DESCRIPTION</H2> 24<B>lua</B> 25is the stand-alone Lua interpreter. 26It loads and executes Lua programs, 27either in textual source form or 28in precompiled binary form. 29(Precompiled binaries are output by 30<B>luac</B>, 31the Lua compiler.) 32<B>lua</B> 33can be used as a batch interpreter and also interactively. 34<P> 35The given 36<I>options</I> 37(see below) 38are executed and then 39the Lua program in file 40<I>script</I> 41is loaded and executed. 42The given 43<I>args</I> 44are available to 45<I>script</I> 46as strings in a global table named 47<B>arg</B>. 48If these arguments contain spaces or other characters special to the shell, 49then they should be quoted 50(but note that the quotes will be removed by the shell). 51The arguments in 52<B>arg</B> 53start at 0, 54which contains the string 55'<I>script</I>'. 56The index of the last argument is stored in 57<B>arg.n</B>. 58The arguments given in the command line before 59<I>script</I>, 60including the name of the interpreter, 61are available in negative indices in 62<B>arg</B>. 63<P> 64At the very start, 65before even handling the command line, 66<B>lua</B> 67executes the contents of the environment variable 68<B>LUA_INIT</B>, 69if it is defined. 70If the value of 71<B>LUA_INIT</B> 72is of the form 73'@<I>filename</I>', 74then 75<I>filename</I> 76is executed. 77Otherwise, the string is assumed to be a Lua statement and is executed. 78<P> 79Options start with 80<B>'-'</B> 81and are described below. 82You can use 83<B>'--'</B> 84to signal the end of options. 85<P> 86If no arguments are given, 87then 88<B>"-v -i"</B> 89is assumed when the standard input is a terminal; 90otherwise, 91<B>"-"</B> 92is assumed. 93<P> 94In interactive mode, 95<B>lua</B> 96prompts the user, 97reads lines from the standard input, 98and executes them as they are read. 99If a line does not contain a complete statement, 100then a secondary prompt is displayed and 101lines are read until a complete statement is formed or 102a syntax error is found. 103So, one way to interrupt the reading of an incomplete statement is 104to force a syntax error: 105adding a 106<B>';'</B> 107in the middle of a statement is a sure way of forcing a syntax error 108(except inside multiline strings and comments; these must be closed explicitly). 109If a line starts with 110<B>'='</B>, 111then 112<B>lua</B> 113displays the values of all the expressions in the remainder of the 114line. The expressions must be separated by commas. 115The primary prompt is the value of the global variable 116<B>_PROMPT</B>, 117if this value is a string; 118otherwise, the default prompt is used. 119Similarly, the secondary prompt is the value of the global variable 120<B>_PROMPT2</B>. 121So, 122to change the prompts, 123set the corresponding variable to a string of your choice. 124You can do that after calling the interpreter 125or on the command line 126(but in this case you have to be careful with quotes 127if the prompt string contains a space; otherwise you may confuse the shell.) 128The default prompts are "> " and ">> ". 129<H2>OPTIONS</H2> 130<P> 131<B>-</B> 132load and execute the standard input as a file, 133that is, 134not interactively, 135even when the standard input is a terminal. 136<P> 137<B>-e </B><I>stat</I> 138execute statement 139<I>stat</I>. 140You need to quote 141<I>stat </I> 142if it contains spaces, quotes, 143or other characters special to the shell. 144<P> 145<B>-i</B> 146enter interactive mode after 147<I>script</I> 148is executed. 149<P> 150<B>-l </B><I>name</I> 151call 152<B>require</B>('<I>name</I>') 153before executing 154<I>script</I>. 155Typically used to load libraries. 156<P> 157<B>-v</B> 158show version information. 159<H2>SEE ALSO</H2> 160<B>luac</B>(1) 161<BR> 162<A HREF="http://www.lua.org/">http://www.lua.org/</A> 163<H2>DIAGNOSTICS</H2> 164Error messages should be self explanatory. 165<H2>AUTHORS</H2> 166R. Ierusalimschy, 167L. H. de Figueiredo, 168and 169W. Celes 170<!-- EOF --> 171</BODY> 172</HTML> 173
