[redis.git] / deps / lua / doc / lua.1

.\" $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $
.TH LUA 1 "$Date: 2006/01/06 16:03:34 $"
.SH NAME
lua \- Lua interpreter
.SH SYNOPSIS
.B lua
[
.I options
]
[
.I script
[
.I args
]
]
.SH DESCRIPTION
.B lua
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
.BR luac ,
the Lua compiler.)
.B lua
can be used as a batch interpreter and also interactively.
.LP
The given
.I options
(see below)
are executed and then
the Lua program in file
.I script
is loaded and executed.
The given
.I args
are available to
.I script
as strings in a global table named
.BR arg .
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
start at 0,
which contains the string
.RI ' script '.
The index of the last argument is stored in
.BR arg.n .
The arguments given in the command line before
.IR script ,
including the name of the interpreter,
are available in negative indices in
.BR arg .
.LP
At the very start,
before even handling the command line,
.B lua
executes the contents of the environment variable
.BR LUA_INIT ,
if it is defined.
If the value of
.B LUA_INIT
is of the form
.RI '@ filename ',
then
.I filename
is executed.
Otherwise, the string is assumed to be a Lua statement and is executed.
.LP
Options start with
.B '\-'
and are described below.
You can use
.B "'\--'"
to signal the end of options.
.LP
If no arguments are given,
then
.B "\-v \-i"
is assumed when the standard input is a terminal;
otherwise,
.B "\-"
is assumed.
.LP
In interactive mode,
.B lua
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 ';' 
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
.BR '=' ,
then
.B lua
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
.BR _PROMPT ,
if this value is a string;
otherwise, the default prompt is used.
Similarly, the secondary prompt is the value of the global variable
.BR _PROMPT2 .
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 ">> ".
.SH OPTIONS
.TP
.B \-
load and execute the standard input as a file,
that is,
not interactively,
even when the standard input is a terminal.
.TP
.BI \-e " stat"
execute statement
.IR stat .
You need to quote
.I stat 
if it contains spaces, quotes,
or other characters special to the shell.
.TP
.B \-i
enter interactive mode after
.I script
is executed.
.TP
.BI \-l " name"
call
.BI require(' name ')
before executing
.IR script .
Typically used to load libraries.
.TP
.B \-v
show version information.
.SH "SEE ALSO"
.BR luac (1)
.br
http://www.lua.org/
.SH DIAGNOSTICS
Error messages should be self explanatory.
.SH AUTHORS
R. Ierusalimschy,
L. H. de Figueiredo,
and
W. Celes
.\" EOF
Commit	Line	Data
21d3294c	1	.\" $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $
	2	.TH LUA 1 "$Date: 2006/01/06 16:03:34 $"
	3	.SH NAME
	4	lua \- Lua interpreter
	5	.SH SYNOPSIS
	6	.B lua
	7	[
	8	.I options
	9	]
	10	[
	11	.I script
	12	[
	13	.I args
	14	]
	15	]
	16	.SH DESCRIPTION
	17	.B lua
	18	is the stand-alone Lua interpreter.
	19	It loads and executes Lua programs,
	20	either in textual source form or
	21	in precompiled binary form.
	22	(Precompiled binaries are output by
	23	.BR luac ,
	24	the Lua compiler.)
	25	.B lua
	26	can be used as a batch interpreter and also interactively.
	27	.LP
	28	The given
	29	.I options
	30	(see below)
	31	are executed and then
	32	the Lua program in file
	33	.I script
	34	is loaded and executed.
	35	The given
	36	.I args
	37	are available to
	38	.I script
	39	as strings in a global table named
	40	.BR arg .
	41	If these arguments contain spaces or other characters special to the shell,
	42	then they should be quoted
	43	(but note that the quotes will be removed by the shell).
	44	The arguments in
	45	.B arg
	46	start at 0,
	47	which contains the string
	48	.RI ' script '.
	49	The index of the last argument is stored in
	50	.BR arg.n .
	51	The arguments given in the command line before
	52	.IR script ,
	53	including the name of the interpreter,
	54	are available in negative indices in
	55	.BR arg .
	56	.LP
	57	At the very start,
	58	before even handling the command line,
	59	.B lua
	60	executes the contents of the environment variable
	61	.BR LUA_INIT ,
	62	if it is defined.
	63	If the value of
	64	.B LUA_INIT
65	is of the form
66	.RI '@ filename ',
67	then
68	.I filename
69	is executed.
70	Otherwise, the string is assumed to be a Lua statement and is executed.
71	.LP
72	Options start with
73	.B '\-'
74	and are described below.
75	You can use
76	.B "'\--'"
77	to signal the end of options.
78	.LP
79	If no arguments are given,
80	then
81	.B "\-v \-i"
82	is assumed when the standard input is a terminal;
83	otherwise,
84	.B "\-"
85	is assumed.
86	.LP
87	In interactive mode,
88	.B lua
89	prompts the user,
90	reads lines from the standard input,
91	and executes them as they are read.
92	If a line does not contain a complete statement,
93	then a secondary prompt is displayed and
94	lines are read until a complete statement is formed or
95	a syntax error is found.
96	So, one way to interrupt the reading of an incomplete statement is
97	to force a syntax error:
98	adding a
99	.B ';'
100	in the middle of a statement is a sure way of forcing a syntax error
101	(except inside multiline strings and comments; these must be closed explicitly).
102	If a line starts with
103	.BR '=' ,
104	then
105	.B lua
106	displays the values of all the expressions in the remainder of the
107	line. The expressions must be separated by commas.
108	The primary prompt is the value of the global variable
109	.BR _PROMPT ,
110	if this value is a string;
111	otherwise, the default prompt is used.
112	Similarly, the secondary prompt is the value of the global variable
113	.BR _PROMPT2 .
114	So,
115	to change the prompts,
116	set the corresponding variable to a string of your choice.
117	You can do that after calling the interpreter
118	or on the command line
119	(but in this case you have to be careful with quotes
120	if the prompt string contains a space; otherwise you may confuse the shell.)
121	The default prompts are "> " and ">> ".
122	.SH OPTIONS
123	.TP
124	.B \-
125	load and execute the standard input as a file,
126	that is,
127	not interactively,
128	even when the standard input is a terminal.
129	.TP
130	.BI \-e " stat"
131	execute statement
132	.IR stat .
133	You need to quote
134	.I stat
135	if it contains spaces, quotes,
136	or other characters special to the shell.
137	.TP
138	.B \-i
139	enter interactive mode after
140	.I script
141	is executed.
142	.TP
143	.BI \-l " name"
144	call
145	.BI require(' name ')
146	before executing
147	.IR script .
148	Typically used to load libraries.
149	.TP
150	.B \-v
151	show version information.
152	.SH "SEE ALSO"
153	.BR luac (1)
154	.br
155	http://www.lua.org/
156	.SH DIAGNOSTICS
157	Error messages should be self explanatory.
158	.SH AUTHORS
159	R. Ierusalimschy,
160	L. H. de Figueiredo,
161	and
162	W. Celes
163	.\" EOF