[Whenever gem]What is the reason that linux's cron can't automatic running?

Cron runs commands with a very limited environment - PATH, for instance, may be missing things that it would have in your normal login shell. It’s typically a good idea to put an explicit path to any executable needed - so /some/path/to/backup instead of just backup.

Digging around in the code for ‘backup’ also shows that you may want to pass --root-path=/wherever/your/app/lives to the script as well, to ensure that it can find the config files, etc that it needs.

–Matt Jones