surfaces.txt unite
npm install -g surfaces_txt_unite
surfaces_txt_unite < surfaces.txt > surfaces.unite.txt
or use this on your program ...
var surfaces_txt_unite = require('surfaces_txt_unite');
var united_txt = surfaces_txt_unite.unite(txt);
or use this on the browsers ...
<script src="surfaces_txt_unite.js"></script>
...
var united_txt = surfaces_txt_unite.unite(txt);