Bash – PS1 Prompt Overwrites First Line

You can access the just-executed command line with the history built-in. (I have no idea why history 1 prints the just-executed command line but fc -nl -1 prints the previous commmand, as does fc -nl 0.)

PROMPT_COMMAND='echo -en "\033[38;5;2m"; history 1; echo -en "\033[0m\n"'

This prints a number before the command text. Here's a version that removes the number. (It may be incorrect if you go beyond 99999 history lines, I don't know how bash formats the number then.)

prompt_function () {
  local prompt_history="$(history 1)"
  prompt_history=${prompt_history:7}
  echo -En $'\033[38;5;2m'"$prompt_history"$'\033[0m\n'
}
PROMPT_COMMAND=prompt_function

(Note that echo -en ..."$prompt_history"... would expand backslashes in the command line, so I use echo -E and let the shell expansion generate the control characters with $''.).

Most of the terminals you are likely to use implement escape sequences for saving and restoring the cursor position. Those are the sc (save cursor) and rc (restore cursor) capabilities in the terminal description, which you can use via tput (just like cup):

tput sc
tput cup 50 10
echo some stuff
echo more stuff
tput rc

However, if your program writes enough text to force scrolling, the restored position will still be on the same place on the terminal's screen. It does not move along with the scrolled text.

POSIX, by the way, documents only part of tput because the tool is actually part of another standard, X/Open Curses. That is summarized in the portability section of the manual page.

Back to the question: there are no escape sequences which track the buffer position (accounting for scrolling). To get that, your application would have to keep track of what was sent to the screen. Solving that sort of problem is what the curses library is for. In a plain command-line application, there is not much that you can do.