Keep Homebrew updated once daily

daily_homebrew_update.sh

# Assuming you open Terminal at least once a day, add this to your shell profile
# (I use zsh, you may require changes for your shell)

function brew_update() {
    brew update
    brew upgrade --all
}

CURR_DATE=`date '+%Y-%m-%d'`
LAST_DATE=`head -n 1 $HOME/.brew_update_date 2>/dev/null`
if [ "$CURR_DATE" != "$LAST_DATE" ]; then
    echo $CURR_DATE > $HOME/.brew_update_date
    echo Updating Homebrew...
    brew_update
fi