First version -- working.

off.sh

@@ -0,0 +1,38 @@
+TIME_START=00:00
+TIME_STOP=23:59
+
+tv_check()
+{
+    ping -c 1 -W 1 192.168.1.12 2>&1 > /dev/null || { echo "TV is unreachable."; return; }
+    adb connect 192.168.1.12
+
+    if adb shell dumpsys power | grep mWakefulness=Awake
+    then
+        adb shell input keyevent 26
+    else
+        echo "TV is turning OFF."
+    fi
+}
+
+gabi_check()
+{
+    loginctl list-users | grep gabi || { echo 'Gabi is not online.'; return; }
+    doas loginctl terminate-user gabi
+}
+
+S=$(date -d "$TIME_START" +%s)
+T=$(date -d "$TIME_STOP" +%s)
+C=$(date +%s)
+if [ $C -lt $S ]
+then
+    echo "PRE: $((S - C)) seconds to go."
+elif [ $C -gt $T ]
+then
+    echo "POST: $((C - T)) seconds passed."
+else
+    echo "ACTIVE: Executing for the next $((T - C)) seconds."
+    gabi_check
+    tv_check
+fi
+
+exit 0