1. Install libnotify-bin which provides notify-send

   sudo apt-get install libnotify-bin
   

2. Create new script:

   import time
   import subprocess
   
   #no need
   #keyboard.release_key("<ctrl>")
   
   # wait_for_keypress does not return any thing to distinguish between target key pressed or timeout reached.
   # So if time is less than the timeout then it was key press.
   start_time = time.time()
   keyboard.wait_for_keypress("1", timeOut=1)
   if (time.time()-start_time < 0.9):
       time.sleep(0.2)
       window.activate("gnu screen")
       time.sleep(0.1)
       active_title = window.get_active_title()
       # if it doesn't get same title, then no window titled as gnu screen
       # it sends a notify message otherwise send the key sequence.
       if (active_title == "gnu screen"):
           keyboard.press_key("<ctrl>")
           keyboard.send_key("a")
           keyboard.release_key("<ctrl>")
           keyboard.send_key("1")
       else:
           subprocess.Popen(['notify-send', "Couldn't find destination window"])
   

3. Setup its hot key as: Ctrl+a

To trigger it: Ctrl+a then 1 (in <1sec)

Debug

1. Launch X Event Tester in separate terminal window

   xev -event keyboard
   

2. Check it's window title, mine shows Event Tester

   $ wmctrl -l
   0x03000012 -1       N/A Desktop — Plasma
   0x030000c1 -1       N/A Desktop — Plasma
   0x0300001b -1       N/A Plasma
   0x06a00098  0        PC User User - Ask Ubuntu - Mozilla Firefox
   0x01a00067  0       N/A user : screen
   0x01a000cd  0       N/A user : xev
   0x04600001  0       N/A Event Tester
   0x01e0015d  0        PC AutoKey
   

3. Modify script to target Event Tester window.

   import time
   import subprocess
   
   start_time = time.time()
   keyboard.wait_for_keypress("1", timeOut=1)
   if (time.time()-start_time < 0.9):
       time.sleep(0.2)
       window.activate("Event Tester")
       time.sleep(0.1)
       keyboard.press_key("<ctrl>")
       keyboard.send_key("a")
       keyboard.release_key("<ctrl>")
       keyboard.send_key("1")
   

4. If xev receives the key sequence. Its output should be some thing similar to:

   KeyPress event, serial 34, synthetic NO, window 0x4600001,
       root 0xb2, subw 0x0, time 55057700, (1053,140), root:(945,303),
       state 0x0, keycode 105 (keysym 0xffe4, Control_R), same_screen YES,
       XLookupString gives 0 bytes: 
       XmbLookupString gives 0 bytes: 
       XFilterEvent returns: False
   
   KeyPress event, serial 34, synthetic YES, window 0x4600001,
       root 0xb2, subw 0x0, time 0, (1,1), root:(1,1),
       state 0x0, keycode 38 (keysym 0x61, a), same_screen YES,
       XLookupString gives 1 bytes: (61) "a"
       XmbLookupString gives 1 bytes: (61) "a"
       XFilterEvent returns: False
   
   KeyRelease event, serial 35, synthetic YES, window 0x4600001,
       root 0xb2, subw 0x0, time 0, (1,1), root:(1,1),
       state 0x0, keycode 38 (keysym 0x61, a), same_screen YES,
       XLookupString gives 1 bytes: (61) "a"
       XFilterEvent returns: False
   
   KeyRelease event, serial 35, synthetic NO, window 0x4600001,
       root 0xb2, subw 0x0, time 55057701, (1053,140), root:(945,303),
       state 0x4, keycode 105 (keysym 0xffe4, Control_R), same_screen YES,
       XLookupString gives 0 bytes: 
       XFilterEvent returns: False
   
   KeyPress event, serial 35, synthetic YES, window 0x4600001,
       root 0xb2, subw 0x0, time 0, (1,1), root:(1,1),
       state 0x0, keycode 10 (keysym 0x31, 1), same_screen YES,
       XLookupString gives 1 bytes: (31) "1"
       XmbLookupString gives 1 bytes: (31) "1"
       XFilterEvent returns: False
   
   KeyRelease event, serial 35, synthetic YES, window 0x4600001,
       root 0xb2, subw 0x0, time 0, (1,1), root:(1,1),
       state 0x0, keycode 10 (keysym 0x31, 1), same_screen YES,
       XLookupString gives 1 bytes: (31) "1"
       XFilterEvent returns: False
   

Note, I have removed the if condition to check active title. The script activates/raises xev window but the check doesn't find the correct title. I got just the notification message.

I was thinking along the same lines as "Mostafa Najafiyazdi" and I used his wmctrl function as a base for first script version of the function with some modifications.

This is not autokey specific and as such it's not a python script. I use similar setup to activate, switch and do some stuff on my media-pc (mythtv) with a single remotecontrol button.

Setting windows shortcut/autokey to run these script with combined keys is difficult and ctrl+a is usually globally something different. If you decide to use something ctrl+f7 for the activation key, then calling this script should do what you want.

This requies xdotool and libnotify-bin. This will not change active window to "gnu screen", see commented section to change to the same functionality as with the activate_window_and_send_keys script.

~/bin/focus_window_and_send_keys "gnu screen" "ctrl+a+1"

And the script:

#!/bin/bash
## copy these files to ~/bin = (~ = is your home directory)
### finding window and keys
## requires xdotool
### notify
## libnotify-bin

# Usage:
# ~/bin/focus_window_and_send_keys "window title" "keys" "morekeys" ...
# ~/bin/focus_window_and_send_keys "gnu screen" "ctrl+a+1"

title=${1:-NOT_FOUND_EMPTY_TITLE}
shift
## get current window
CURWIN=$(xdotool getactivewindow)
TARGETWIN=$(xdotool search --name "$title" | head -n 1)
if [ -z $TARGETWIN ]; then
 notify-send -i face-crying "Can't find specified window!"
else
  ## use this to activate window
  #xdotool windowactive "$TARGETWIN"
  ## changes focus, does not change to the window on display
  xdotool windowfocus "$TARGETWIN"
  ## send keys if window was found
  for keypress in "$@"
  do
    xdotool key --window "$TARGETWIN" "$keypress"
  done
fi
## comment next line if focus should stay with activated window
xdotool windowfocus "$CURWIN"

My first version required these and is functional (below), but uses extra wrapper and needs window to be active. xdotool version does not require that.

This requires xautomation libnotify-bin and wmctrl

this is ~/bin/activate_window_and_send_keys scipt To do what you want from cmdline, you'd call this with

# this is press ctrl, a, 1, release ctrl
~/bin/activate_window_and_send_keys "gnu screen" "ctrl+a+1"
# this is press ctrl, a, release ctrl, 1
~/bin/activate_window_and_send_keys "gnu screen" "ctrl+a" "1"

Remember to chmod u+x on your ~/bin/* scripts

#!/bin/bash
## copy these files to ~/bin (~ = is your home directory)
### finding window
## requires wmctrl
### notify
## libnotify-bin
### tool to send keypresses
## requires xautomation

# Usage:
# ~/bin/activate_window_and_send_keys "window title" "keys" "morekeys" ...
# ~/bin/activate_window_and_send_keys "gnu screen" "ctrl+a+1"

export PATH=$PATH:~/bin


## helper function to find correct window
## modified version of Mostafa Najafiyazdi answer
## http://askubuntu.com/a/637897/41757
function find_window_and_activate_window {
  # Get the list of all windows
  # and select the line containing a substring given as
  # an argument to the script
  title=$1
  window_found=`wmctrl -l | grep "$title" | awk '{print $3}'`
  # If nothing is found, echo a message
  if [ -z "$window_found" ]; then
    notify-send -i face-crying "Can't find specified window!"
    return -1
  else
    wmctrl -a "$title"
  fi
}

title=${1:-NOT_FOUND_EMPTY_TITLE}
shift
echo "$title"
find_window_and_activate_window "$title" && {
   ## send keys if window was found
   for keypress in "$@"
   do
     sendkey "$keypress"
   done
}

This is ~/bin/sendkey It is simply a wrapper around xte to simplify xte syntax

#!/usr/bin/perl

my @keys=@ARGV;
for my $key (@keys) {
  my @keycomb=split(/\+/, $key);
  my $k = pop(@keycomb);
  #print "$k\n";
  my $modup   = "";
  my $moddown = "";
  my $press   = " 'key $k' ";
  for my $m (@keycomb) {
    $m =~ s/ctrl/Control_L/gi;
    $m =~ s/alt/Alt_L/gi;
    $m =~ s/shift/Shift_L/gi;
    $moddown = $moddown.' "keydown '.$m.'"';
    $modup   = ' "keyup '.$m.'"'.$modup;
  }
  system("xte $moddown $press $modup");
}

The first thing that comes to my mind is to break what you want to do in two parts:

1. Writing a bash function which checks for a window titled whatever you want, for you it would be 'gnu screen', if not found pops up a message saying "Couldn't find destination window!" For this you would first need to install wmctrl

   sudo apt-get install wmctrl
   

   It is a windows controller which you can use to get windows information including its PID, title, position, size, desktop number, etc. Add the following code in your .bash_aliases:

   function find_window {
     # Get the list of all windows 
     # and select the line containing a substring given as 
     # an argument to the script
     title=$1
   
     window_found=`wmctrl -l | grep $title | awk '{print $3}'`
   
     # If nothing is found, echo a message
     if [ -z "$window_found" ]; then
       notify-send -i face-crying "Can't find specified window!"
     else
       wmctrl -a $1
     fi
   }
   

   You can change how the notification looks like. Just see the manpage for notify-send.

2. Define a custom short using your system settings. See here Simple add find_window "gnu screen" as the command to run. You define keyboard sequences as you like.

EDIT: If the window exists, it will switch to that window! That's what the else in the if then else does.