example data dump with retry on failure

backup.sh

#!/bin/bash

result=
while (( $result )) || [ -z "$result" ]; do
  node dump_data_for_backup.js  > backup.json

  result=$?
  # there is no way to distinguish node's (1) exit code on SIGINT (and SIGTERM)
  # from a (1) exit code due to normal exit call in userland.
  # if node preserved SIGINT/SIGTERM, then the shell would detect node's
  # "abnormal exit" status, and the script would terminate right here.
  
  # as it stands, it will be very difficult to terminate this script
  # using Ctrl-C (SIGINT) or SIGTERM.

  if (( $result != 0 )) ; then 
    echo -e "\nbackup failed ($result). retrying..."
  fi
done
echo ">> backup-$(date +%Y%m%d).json"