____  _              _            _                     _
 |  _ \(_)_ __   ___  | |_ _____  _| |_    __ _ _ __   __| |
 | |_) | | '_ \ / _ \ | __/ _ \ \/ / __|  / _` | '_ \ / _` |
 |  __/| | |_) |  __/ | ||  __/>  <| |_  | (_| | | | | (_| |
 |_|   |_| .__/ \___|  \__\___/_/\_\\__|  \__,_|_| |_|\__,_|
  _      |_|
 | | _____ _   _       _ __  _ __ ___  ___ ___  ___  ___
 | |/ / _ \ | | |_____| '_ \| '__/ _ \/ __/ __|/ _ \/ __|
 |   <  __/ |_| |_____| |_) | | |  __/\__ \__ \  __/\__ \
 |_|\_\___|\__, |     | .__/|_|  \___||___/___/\___||___/
           |___/      |_|
           _ _   _       _
 __      _(_) |_| |__   | |_ _ __ ___  _   ___  __
 \ \ /\ / / | __| '_ \  | __| '_ ` _ \| | | \ \/ /
  \ V  V /| | |_| | | | | |_| | | | | | |_| |>  <
   \_/\_/ |_|\__|_| |_|  \__|_| |_| |_|\__,_/_/\_\

        [Pipe text and key-presses with tmux]
  by TheOuterLinux (https://theouterlinux.gitlab.io)
  
  Last updated: 2023/05/13
  
Tmux is a terminal multiplexer; meaning, you can have one terminal
window but split it into multiple terminals. However, it does have one
very interesting feature: "send-keys." Using the "send-keys" argument,
you can... drum-roll... send keyboard presses to a tmux session; you no
longer have to run an 'xmacro' program, which do not work in TTY, to do 
things automatically in command-line programs that have their own shell.

Maybe this will make more sense with an example. Let's say that one day
you felt like playing around with FluidSynth but wanted to use the shell
except have a bunch of things done automatically for you. When the 
'fluidsynth' program is ran by itself, you get a shell like so:

    FluidSynth runtime version 2.2.3
    Copyright (C) 2000-2021 Peter Hanappe and others.
    Distributed under the LGPL license.
    SoundFont(R) is a registered trademark of Creative Technology Ltd.

    Type 'help' for help topics.

    >

If we wanted a "one-liner" to use 'tmux' to open 'fluidsynth' and then 
have it also run "help" within fluidsynth's shell, do something like so:

    tmux new-session -s TITLEOFSESSION fluidsynth \; send-keys "help" Enter

...The above opens a tmux session, gives it the name "TITLEOFSESSION,"
runs 'fluidsynth,' and then sends the text "help," followed by an Enter
key-press. However, let's say you wanted more key-presses...

    tmux new-session -s TITLEOFSESSION fluidsynth \; send-keys "help" Enter \; send-keys "help player" Enter \;
    
HOWEVER, you can also send key-presses from another terminal using:

    tmux send-keys "help" Enter
    
...assuming that you only have one tmux session running.

Another program out there is called 'expect,' but it is only good for
running against BASH scripts that use the 'read' command. Also the
multitude of suggestions to use 'echo' and "> /dev/pts/#" together may
pipe text to another terminal, but "\n" only does a new-line, not an
actual Enter/Return key-press when it comes to another program's shell.