Simple bash history auto backup

bash_history_auto_backup.sh

# copy to your .bashrc to keey bash history backups at ~/bak/bash/history/

# backup bash history when start new bash session and there no bak files for last 5 minutes
LAST_HIST_BAKS=$(find  $HOME/bak/bash/history/ -type f -mmin -5)
if [ -z "$LAST_HIST_BAKS" ]; then
  mkdir -p $HOME/bak/bash/history/
  zstd < $HOME/.bash_history > $HOME/bak/bash/history/bash_history.$(date +%Y-%m-%d_%H-%M-%S.%N).zst
  
  # remove old (older then 30 days) bak files
  find  ~/bak/bash/history/ -type f -mtime '+30' | xargs --no-run-if-empty rm
fi