python - Keep stdin line at top or bottom of terminal screen -

so writing project run program receives/sends messages other computers running same program.

the receiver/sender of data running on thread , prints stdout. stuff this:

[info] user 'blah' wants send message you. [info] other info [msg rec] message 'hello' received blah. 

now issue wish input commands terminal, problem when try enter command , new info message or msg rec printed stdout. have commands such quit , status etc.

>> indicates input line.

something may happen:

[info] user 'blah' wants send message you. [info] other info [msg rec] message 'hello' received blah. >> stat[msg rec] message 'sup' received bob. 

then press enter , command status gets executed looks poor in terminal. message appears every 2-4 seconds issue. there way solve this? tried using ansi cursor commands try , insert new line before last line last line remain input line , type in "stat", wait while , finish "us" without issues.

i saw people recommend curses attempting integrate program messed formatting of output among other things (and think overkill perhaps).

so there easy way make thread insert new msg rec lines 1 line above last line last line remain input line >> , whatever else have typed in.

using python2.7 on linux.

edit: change made james mills answer work: had use whenever thread printing new line.

myy, myx = stdscr.getyx();         str = "blah blah"; #my message want print stdscr.addstr(len(lines), 0, str) lines.append(str) stdscr.move(myy, myx) #move cursor proper position 

here basic example:

code:

#!/usr/bin/env python  string import printable curses import erasechar, wrapper  printable = map(ord, printable)  def input(stdscr):     erase = input.erase = getattr(input, "erase", ord(erasechar()))     y, x = stdscr.getyx()     s = []      while true:         c = stdscr.getch()          if c in (13, 10):             break         elif c == erase:             y, x = stdscr.getyx()             if x > x:                 del s[-1]                 stdscr.move(y, (x - 1))                 stdscr.clrtoeol()                 stdscr.refresh()         elif c in printable:             s.append(chr(c))             stdscr.addch(c)      return "".join(s)  def prompt(stdscr, y, x, prompt=">>> "):     stdscr.move(y, x)     stdscr.clrtoeol()     stdscr.addstr(y, x, prompt)     return input(stdscr)  def main(stdscr):     y, x = stdscr.getmaxyx()      lines = []     max_lines = (y - 3)      stdscr.clear()      while true:         s = prompt(stdscr, (y - 1), 0)  # noqa         if s == ":q":             break          # scroll         if len(lines) > max_lines:             lines = lines[1:]             stdscr.clear()             i, line in enumerate(lines):                 stdscr.addstr(i, 0, line)          stdscr.addstr(len(lines), 0, s)         lines.append(s)          stdscr.refresh()  wrapper(main) 

this sets demo curses app prompts user input , displays prompt @ (24, 0). demo terminates on user entering :q. other input appends input top of screen. enjoy! (<backsapce> works!) :)

see: curses; of api used in example straight standard library. whilst using curses may or may not "overkill" ihmo recommend use of urwid if complexity of application starts outgrow plain 'ol curses.