Lua strings 'n' things

New to Lua, need to check if a string exists inside another string, and can't seem to figure it out, how do I?

In PHP this'd be:

<?php
$pos = strpos($haysta开发者_运维技巧ck,$needle);

if($pos === false) {
 // string needle NOT found in haystack
} else {
 // string needle found in haystack
}
?>

Also need to chop off the last char of a string...

http://lua-users.org/wiki/StringLibraryTutorial

print(string.find("foobar", "foo"))

yields...

1   3

print(string.find("foobar", "baz"))

yields...

nil

print(string.sub("foobar", 1, 5))

yields...

fooba

For chopping the last character, you can use a negative index:

string.sub("the string.", 1, -2)