O yeah, one more thing. The initial link you sent me contains the snippet that is written to file using cat but for me it only works with simply echo on a single line. If I copy from the website, it inserts weird end of line characters that mess it up (at least that's my hypothesis) - so you might want to consider putting a warning on the website or updating to the instruction below

echo 'db.model.find({uri:{$regex:/^http:\/\/10\.0\.0\.12:8081/}}).forEach(function(e,i) { e.uri = e.uri.replace("

","newaddress:port"); db.model.save(e);});' > script.js