backup copy of a single-user `brew` installation

brewinst.sh

# change to whatever location to where homebrew is installed
if [ -z "$HOMEBREW_HOME" ]; then
  export HOMEBREW_HOME=$HOME/homebrew
  echo "HOMEBREW_HOME=$HOME/homebrew" >> ~/.profile
fi

# install homebrew for single user
if [ ! -d "$HOMEBREW_HOME" ]; then
  mkdir -p $HOMEBREW_HOME && curl -L https://github.com/Homebrew/homebrew/tarball/master | tar xz --strip 1 -C $HOMEBREW_HOME
fi

# add the new homebrew bin directory to the path
if [ -z `echo $PATH | grep "$HOMEBREW_HOME"` ]; then   
  echo "PATH=$HOMEBREW_HOME/bin:$PATH" >> ~/.profile
  export PATH=$HOMEBREW_HOME/bin:$PATH
fi

# configure the local homebrew cache directory
if [ -z "$HOMEBREW_CACHE" ]; then
  echo "HOMEBREW_CACHE=$HOME/Library/Caches/Homebrew" >> ~/.profile
  export HOMEBREW_CACHE=$HOME/Library/Caches/Homebrew
fi

If you see the following:

Updating Homebrew...
Error: Could not link:
/Users/GoodPersonUser/homebrew/share/doc/homebrew

Please delete these paths and run `brew update`.
...

you can safely delete ~/homebrew/share/doc/homebrew; I dunno when this happened, but it only happens with new installs (and thus I've not had a chance to test it, as I only end up with a new mac every few years. I probably should figure out where in the install process I can delete that, but for now, it's safe to delete that path if you see it.