When I run an apt-get update, apt-get dist-upgrade, the location of /usr/bin/ruby changes from /usr/local/bin/ruby to /etc/alternatives/ruby. This ends up breaking several cron jobs until I remember to correct it back. Why is it doing this?
Don't move the binary, symlink it
but better yet use update-alternatives
Oh and the why, there are multiple branches of ruby (ruby1.8 vs ruby1.9) similar to python2 vs python3 which affect script compatibility.