unlimited bash history

.bashrc

export PATH=$(brew --prefix coreutils)/libexec/gnubin:$PATH

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=-1
HISTFILESIZE=-1
#HISTFILE="${HOME}/.history/$(date -u +%Y/%m/%d.%H.%M.%S)_${HOSTNAME_SHORT}_$$"
HISTFILE="${HOME}/.history/$(date -d 'last sat +1 day' +%Y/%V/%m.%d)_${HOSTNAME%%.*}"
mkdir -p "$(dirname "$HISTFILE")"

# other stuff ...

This requires GNU date command from Homebrew, hence PATH needs to be set first.