code: function unzipInTmpDir(base64) {
          var mkTempCmd = "mktemp -d XXXXXXXX";
          return exec(mkTempCmd).then(function (tmpDir1) {
              return new Promise(
                  function (resolve, reject) {
                      var zipFile = path.join(tmpDir1, "action.zip");
                      fs.writeFile(zipFile, base64, "base64", function (err) {
                          if (err) {
                              reject("There was an error reading the action archive.");
                          }
                          resolve(zipFile);
                      });
                  }
              );
          }).then(function (zipFile) {
              return exec(mkTempCmd).then(function (tmpDir2) {
                  return exec("unzip -qq " + zipFile + " -d " + tmpDir2).then(function (res) {
                     return path.resolve(tmpDir2);
                  }).catch(function (error) {
                     return Promise.reject("There was an error uncompressing the action archive.");
                  });
              });
          });
      }
docs: Helper function to copy a base64-encoded zip file to a temporary location, decompress it into temporary directory, and return the name of that directory. Note that this makes heavy use of shell commands because: 1) Node 0.12 doesn't have many of the useful fs functions. 2) We know in which environment we're running.