Ubuntu 14.04 has nodejs installed instead of node, but the error message from phonegap is dubious. Took me a bit of time to realize what went wrong.
Error syndrome: successfully installed phonegap using the following command.
sudo npm install -g cordova sudo npm install -g phonegap
However, error message /usr/bin/env: node: No such file or directory appears when typing command phonegap in terminal.
ln -s /usr/bin/nodejs /usr/bin/node