Preserve multi-tab history in ptyaxis

ptyxis-history

# Drop this file into ~/.bashrc.d/ptyxis-history

HISTDIR=~/.history
HISTFILE="$HISTDIR/$$"

mkdir "$HISTDIR" 2>/dev/null

function get_peers() {
  ps --no-headers -o pid --ppid $PPID
}

function filter_level0_shells() {
  xargs -I'{}' sed -n 's/.*SHLVL=0.*/{}\n/p' /proc/'{}'/environ
}

function get_history_files() {
  (cd "$HISTDIR" && ls)
}

function get_orphaned_history_files() {
  get_history_files |fgrep -v -f <(get_peers |filter_level0_shells)
}

function adopt_a_history_file() {
  for histfile in $(get_orphaned_history_files) ;do
    if (cd "$HISTDIR" && flock .LOCKFILE sh -c "[ -f '$histfile' ] && mv '$histfile' '$HISTFILE'") ;then
      return 0
    fi
  done
  return 1
}

if ! adopt_a_history_file; then
  >"$HISTFILE"
fi