Ensure successful execution of script on remote server

Question

I have a script on a local system which invokes a script on the remote server (server A) to execute. The command in script which triggers remote server script looks like

ssh <user>@<server ip> "bash -s < ./shell_backup_trx_db.sh"

Script shell_backup_trx_db.sh on remote server takes database backup and puts it on server A file system. How can I ensure inside the script on local which uses the above command that the ssh command executed successfully and continue script execution ahead or else abort it?

Answer 1

As long as the remote script returns an appropriate exit code, you shouldn't have a problem to do this.

Just use the conditional control operator && which continues with the next command only if the previous command exited without an error:

ssh <user>@<server ip> "/path/to/shell_backup_trx_db.sh" && echo "Done with backup"

Edit: If you want to execute multiple commands based on whether the ssh command passes or fails, you can use an if..else..fi statement.

Example:

if ssh <user>@<server ip> "/path/to/shell_backup_trx_db.sh";
then
  echo "Backup completed successfully";
  ./next_script.sh;
else
  echo "Backup failed";
  exit;
fi

Answer 2

To exit your script when ssh fails (for whatever reason) you can use something like this.

if ! ssh ...; then
    echo ssh failed
    exit
fi

Answer 3

thanks to @Chirag and @Etan for their valuable answers, with their help ended up with.

  if ssh <user>@<server-ip> stat shell_backup_trx_db.sh \> /dev/null 2\>\&1
  then
    # Trigger Production Database back for both mysql and mongo.
   ssh <user>@<server-ip> "bash -s < ./shell_backup_trx_db.sh"

   echo "Database backup successfully completed."

   # Prompt user to check manually that database backup is completed successfully.
   read -p "Ensure database backup process is successfully completed. Login to dev/stg server and run 'ls command'. Press [Enter] key to continue execution."
  else 
    # Backup script could not be accessed, abort script execution any further. 
    echo "Back up script not found, aborting script execution, Please take backup before." 1>&2
    exit 1
  fi