After handling the options , the Lua program in file script is loaded and executed. The args are available to script as strings in a global table named arg and also as arguments to its main function. When called without arguments, lua behaves as "lua -v -i" if the standard input is a terminal, and as "lua -" otherwise.
In interactive mode, lua prompts the user, reads lines from the standard input, and executes them as they are read. If the line contains an expression, then the line is evaluated and the result is printed. 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.
Before handling command line options and scripts, lua checks the contents of the environment variables LUA_INIT_5_4 and LUA_INIT , in that order. If the contents are of the form '@ filename ', then filename is executed. Otherwise, the contents are assumed to be a Lua statement and is executed. When LUA_INIT_5_4 is defined, LUA_INIT is ignored.
-e " stat" execute statement stat .
-i enter interactive mode after executing script .
-l " mod" require library mod into global mod .
-l " g=mod" require library mod into global g .
-v show version information.
-E ignore environment variables.
-W turn warnings on.
-- stop handling options.
- stop handling options and execute the standard input as a file.
LUA_INIT, LUA_INIT_5_4 Code to be executed before command line options and scripts.
LUA_PATH, LUA_PATH_5_4 Initial value of package.cpath, the path used by require to search for Lua loaders.
LUA_CPATH, LUA_CPATH_5_4 Initial value of package.cpath, the path used by require to search for C loaders.
The documentation at lua.org, especially section 7 of the reference manual.