Backup File Sentry: Engineering a Backup Agent for Field Conditions

Software behaves impeccably on the machine that built it. The interesting failures start afterwards, in front of somebody who did not write it and reports the problem as “it didn’t work”. Backup File Sentry is a NotAnother tool for that setting: a command-line agent in TypeScript on Bun that moves configured files between a client machine and an FTP server, both ways. Moving the bytes is the easy part; the harder question is what happens to the program once nobody who understands it is in the room.