How to make Kaleidoscope your default Git Diff and Merge tool

First you need to grab the ksdiff command line tool and install it

Then the following set of commands will set kaleidoscope to be your default diff/merge tool

git config --global diff.tool kaleidoscope
git config --global difftool.kaleidoscope.cmd '/usr/local/bin/ksdiff --diff "$LOCAL" "$REMOTE"'
git config --global merge.tool kaleidoscope
git config --global mergetool.kaleidoscope.trustExitCode true
git config --global mergetool.kaleidoscope.cmd '/usr/local/bin/ksdiff --merge "$LOCAL" "$REMOTE" --base "$BASE" --output "$MERGED"'

Then to run it

$ git difftool FILE1 FILE2
$ git mergetool