Getting part of a string

["Aggelos Kolaitis" <neoaggelos@...>]

I'm relatively new to scripting with Lua, ( I use it mostly for writing premake scripts). 

Anyway, I would like to know how it could be possible to extract parts of a string. Since I can't specify exactly what I want, I will tell you with an example. 

I handle all the command line arguments given to the script via a global _ARGS table. What I want is to handle arguments like --prefix=path.

(Check if the argument starts with --prefix=, and if so get the path value)

So How can I get the value of path only, which practically means the contents of a string after a given index.

Is something like that possible ?

Thanks in advance,

Aggelos Kolaitis