• 1: It requires creating two TRIGGER.cmd dummy scripts (dummy1 & dummy2) that simply echo "OK" when ran from command line.
• 2: At the end of the backup script have them triggered (using the tcmd tool found here https://www.triggercmd.com/forum/topic/196/tcmd-go-command-line-tool-is-available-now) based 1 on a fail and other on a succeed result.
• 3: In Alexa routines create two, one for dummy1 that Alexa says something like, "Trigger C M D reports script succeeded"
  The other for dummy2 that Alexa says something like, "Trigger C M D reports script failed"

This way you can use the same routines and dummy scripts for several different long running scripts and even for scripts that aren't started by TRIGGERcmd

So if your backup is really quick, it will work. You need to run the SendResult.bat or SendResult.sh script from the script your command ran within about 6 seconds. That's about all Google Assistant and Alexa allow for a reply to a voice command.

This is a little complicated, but it would work:

1. At the end of your backup script, write the result to a file saying "succeeded" or "failed".
2. After that, the same script would run another TRIGGERcmd command using curl or the tcmd tool that does nothing (just have it run echo), but it's tied to an Alexa routine.
3. The Alexa routine's action would run a third triggercmd command with result in the voice field using a custom action that says, "ask TRIGGER C M D to run result".
   
4. The command with result as its voice word will run a script that reads the file your backup script wrote, then either run ~/.TRIGGERcmdData/sendresult.sh succeeded or ~/.TRIGGERcmdData/sendresult.sh failed depending on what it finds in that file.
5. Your Alexa will say, "The backup succeeded" if you have this in your Voice Reply field and the backup succeeded. {{result}} is a placeholder for what you send back with the sendresult.sh script.
   

Notice too I picked my Office Alexa as the one that will say the result of the backup.

You'll need the TRIGGERcmd skill enabled for this to work. Or enable the TRIGGER command skill and substitute "ask TRIGGER C M D to run result" above with "ask trigger command to run result".

If you wish to trigger without Alexa and get Alexa to reply when it is finished you'd need something like https://voicemonkey.io/
TRIGGERcmd can't currently do this..

For example, if I'm doing it without alexa, say running a simple script of echo "hello", I want to know if that was successful or make alexa say "X was done successfuly" or not if it didn't, know what I mean?