curl -o LATEST build.chromium.org/f/chromium/snapshots/chromium-rel-mac/LATEST
latest=`cat LATEST`
rm -rf LATEST
curl -o chrome-mac.zip build.chromium.org/f/chromium/snapshots/chromium-rel-mac/$latest/chrome-mac.zip
unzip chrome-mac.zip
rm -rf chrome-mac.zip
killall Chromium-Exec
rm -rf /Applications/Chromium.app
mv chrome-mac/* /Applications
rm -rf chrome-mac
mv /Applications/Chromium.app/Contents/MacOS/Chromium /Applications/Chromium.app/Contents/MacOS/Chromium-Exec
echo "#!/bin/sh" > /Applications/Chromium.app/Contents/MacOS/Chromium
echo "exec /Applications/Chromium.app/Contents/MacOS/Chromium-Exec --enable-default-apps $@" >> /Applications/Chromium.app/Contents/MacOS/Chromium
chmod +x /Applications/Chromium.app/Contents/MacOS/Chromium

On Mac OS X, there is no easy way (or there wasn't when I wrote this last year) to update Chromium to the latest nightly release. This script will check what the latest version is, download it, and extract it to your applications folder, replacing the previous version. It will kill Chromium beforehand, to be sure there are no resource conflicts as well.

The second last line allows you to add command line parameters, which are rarely used in Chromium 10, however I left an old parameter there as an example.