http://www.google.com/search?hl=en&client=firefox-a&channel=s&rls=org.mozilla%3Aen-US%3Aofficial&hs=ODd&q=jhead&btnG=Search
jhead - Google Search
http://www.sentex.net/~mwandel/jhead/
Exif Jpeg header manipulation tool

download and move prebuilt binary for osx to /usr/local/bin
sudo mv ~/Downloads/jhead /usr/local/bin
sudo chmod +x /usr/local/bin/jhead