To start developing NSE scripts, you don't need anything but a fresh copy of Nmap and your favorite text editor (vi, nano, gedit, and so on). However, you need to configure your text editor to use two space indents instead of tabs if you are planning on sending your contributions to the development mailing list.
There is a file named
HACKING in your Nmap installation directory that you should read. It contains useful tips for people interested in NSE development. If you are working with vi, you might want to add the following to your
.vimrc file. It contains a couple of additions to the rules listed in the
syntax enable au BufRead,BufNewFile *.nse set filetype=lua set nocindent set expandtab set ...