#!/bin/sh -eu

directory="$XDG_DATA_HOME/bash"
persist="$directory/history"
default="$HOME/.bash_history"
current="$HISTFILE"

_prune() {
 sed --in-place '/^#/d' "$1" &&            # Remove all timestamps.
 sed --in-place '/......../!d' "$1" &&     # Remove all commands 8 characters or less.
 sort --unique "$1" | sponge "$1"          # Remove all duplicate entries.
}

mkdir --parents "$directory"
touch "$current"

_migrate() {
 [ -f "$default" ] &&
  cat "$default" >>"$persist" &&
  _prune "$persist" &&
  rm "$default"
}

_store() {
 cat "$current" >> "$persist" &&
 _prune "$persist" &&
 true > "$current"
}

_migrate || true
_store