PROMPT_COMMAND

foo.sh

if [ -z "$PROMPT_COMMAND" ]; then
  case $TERM in
  xterm*|vte*)
    # check /etc/sysconfig and /etc/default for expert custom file first
    # Debian example: 'echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"'
    if [ -e /etc/sysconfig/bash-prompt-xterm ]; then
      PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm
    elif [ -e /etc/default/bash-prompt-xterm ]; then
      PROMPT_COMMAND=/etc/default/bash-prompt-xterm
    elif [[ -e "${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-xterm" ]]; then
      PROMPT_COMMAND=${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-xterm
    elif [ "${VTE_VERSION:-0}" -ge 3405 ]; then
      # If not found, search for vte.sh only if we're in a libvte terminal.
      if [ -r /etc/profile.d/vte.sh ]; then
        . /etc/profile.d/vte.sh && PROMPT_COMMAND="__vte_prompt_command"
      elif [ -r /etc/profile.d/vte-2.91.sh ]; then
        . /etc/profile.d/vte-2.91.sh && PROMPT_COMMAND="__vte_prompt_command"
      elif [ -r /etc/local/profile.d/vte.sh ]; then
        . /etc/local/profile.d/vte.sh && PROMPT_COMMAND="__vte_prompt_command"
      else
        for v in /etc/profile.d/vte*.sh; do
          if [ -r "$v" ]; then
            . "$v" && PROMPT_COMMAND="__vte_prompt_command"
          else
            # no file found so we fallback to hardcoded default.
            PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'
          fi
        done
        unset v
      fi
    else
      # Else no prompt or vte file found, or not in a libvte compatible terminal,
      # fallback to hardcoded default.
      PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'
    fi
    ;;
  screen*)
    # same thing, check if custom file first, else use fallback.
    if [ -e /etc/sysconfig/bash-prompt-screen ]; then
      PROMPT_COMMAND=/etc/sysconfig/bash-prompt-screen
    elif [ -e /etc/default/bash-prompt-screen ]; then
      PROMPT_COMMAND=/etc/default/bash-prompt-screen
    elif [[ -e "${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-screen" ]]; then
      PROMPT_COMMAND=${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-screen
    else
      PROMPT_COMMAND='printf "\033k%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'
    fi
    ;;
    #tmux*) # Should we add another case for tmux or byobu? Or do most use screen/xterm termcaps?
    #;;# The catchall below seems to work, might have to add more and unset there.
  *)
    if [ -e /etc/sysconfig/bash-prompt-default ]; then
      PROMPT_COMMAND=/etc/sysconfig/bash-prompt-default
    elif [ -e /etc/default/bash-prompt-default ]; then
      PROMPT_COMMAND=/etc/default/bash-prompt-default
    elif [[ -e "${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-default" ]]; then
      PROMPT_COMMAND=${XDG_CONFIG_HOME:-$HOME/.config}/bash-prompt-default
    else
      # TODO: test if this breaks anything, seems to work in tmux and ssh terms where others didn't.
      PROMPT_COMMAND='printf "\033k%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}"'
    fi
    ;;
  esac
fi