javascript:
var asdf = (window.getSelection && window.getSelection().toString()) || null;
if (!asdf || asdf === "") {
  try {
    asdf = document.getElementsByClassName('gh-header-title')[0].innerText
  } catch (e) {}
}

if (!asdf) {
  asdf = prompt("Enter the title");
}

try {
  asdf = "gem " + /.*#(.*)/.exec(asdf)[1] + " " + /(.*) #/.exec(asdf)[1];
asdf = asdf.replace(/[ :]/g, "-").replace(/--/, "-");
alert(asdf);
} catch (e) {
  alert("invalid input");
}