this post was submitted on 09 Dec 2023
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Context:
I have 2 Terminals open, in one is a Python Terminal Chat client running(pt3). I want to sent text from the other terminal(pt2) to the chat. It does write the text to pt3 but pt3 dosent 'see' the text.
If i send over "hallo world" it prints on the terminal but dosent show up in chat.
github of the python termina terminal chat
My first thought was, can you flush the buffer?
A PTS is a single character device. Writing to it causes output to appear on the terminal buffer, reading from it reads from the input buffer. So, writing to it like you do from a separate shell effectively does the same as calling print() from python which has it as inherited stdio. There is a way to write to a PTS input buffer but it's not straightforward and works in a completely different way. Use something like tmux instead, or better, sockets.
thank you!
tmux did thr tick for me
Just guessing here but could it be because you haven't set up correctly pt2 as stdin for pt3, try to invoke the command as
This is because the "tty" (by which I mean the device named by the output of ´tty´) is only displaying what is sent to it. Be it from the keyboard or pty2.
The fact that the keyboard also fills an input buffer from python has to do with how python and the keyboard are attached to the same input file device which is a separate thing from them having same output file device.
If anything that could output to tty2 could inject inputs to something using tty2 as an input buffer, that would be a security nightmare.
Now, I'll sit back and let Cunningham's law kick in.
Named pipes are your friends. Or sockets.
With the correct permission you should be able to write straight into pythons stdin from /proc like
Cat whatever > /proc/$pythonpid/fd/0
https://unix.stackexchange.com/questions/281319/tool-to-watch-other-ttys-for-linux
I've not played with it, but I used bsd "watch" and this is advertised as similar.