Ubuntu – How to remove/change the message displayed when opening a terminal

You're lucky, screen does honor save and resore commands. So with bash it can be done.

This gives instructions how to move the cursor around with special escape sequences. You can write "Hello World!" to the top left corner with this:

echo -e "\033[s\033[2;0HHello World!            \n                        \033[u"

Explained: The character \033[s saves the current cursor position, which is what we want b/c screen terminal sizes can vary, a lot. Then \033[2;0 moves the cursor to the third row to the first character (we begin counting in the top left corner and with 0). Then comes the text and a little illustration of what is possible. Finally the code \033[u puts the cursor back to where it was wenn \033[s was emmited.

This example moves the cursor to the second row because when issuing the command 2 newlines are printed so what is the current third row will be the first row.

You can use this together with the session caption you can already get by the explanation you already linked.

When you run a new terminal emulator, that creates a new terminal (/dev/pts/NUMBER on Linux). A program doesn't have to be started by that terminal to output there (try running tty in a terminal, then in another terminal run echo hello >/dev/pts/NUMBER). So you can tell your Python script to read and write from the terminal; all you need is to find out the path to the device file.

With xterm, it's pretty easy: run xterm -e 'tty >&3; myCommand' with file descriptor 3 connected to a pipe from which your program reads the path to the terminal device.

p = subprocess.Popen("xterm -e 'tty >&3; exec sleep 99999999' 3>&1",
                     shell=True, stdout=subprocess.PIPE)
tty_path = readline(p.stdout)
tty = open(tty_path, 'r+')

Your Python program can now read and write to tty. When you've finished, kill the terminal emulator (os.kill(p.pid, signal.SIGTERM)).

With a terminal emulator that's based on a single process for multiple windows such as xfce4-terminal, what you want to do is considerably harder. Running xfce4-terminal breaks links between the parent process and the child of the terminal emulator, and doesn't give you a nice PID that you can kill. You could use a named pipe to communicate but it's a bot harder to set up.