I know this is probably an error on my side rather than with Trello itself, but I assumed that if I posted the question, the answers would be useful for other Trello users too.
I'm trying to use curl to access the Trello JSON export (in order to create a cron job that backups our Trello board every night), but I must be doing something wrong.
1) Perform a login, and store the Trello cookies.
curl -v --user [USER]:[PASSWD] -c cookies.txt --user-agent "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/18.6.872.0 Safari/535.2 UNTRUSTED/1.0 3gpp-gba UNTRUSTED/1.0" https://trello.com/authenticate
2) Invoke the JSON export url, using the stored cookies.
curl -v -b cookies.txt --user-agent "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/18.6.872.0 Safari/535.2 UNTRUSTED/1.0 3gpp-gba UNTRUSTED/1.0" [TRELLO JSON EXPORT URL]
Result: unauthorized error.
If anyone could help me with this, I'd really appreciate it.