Is there a way to download an MMS from command line using curl or wget?

I hope you get an answer to this. I'm not the one, but will throw in my 2 cents worth of advice...

Short version

• You can't have texts skipping the "send to" SIM card and auto-diverting to some computer.

• Make an Android app to install on your phone, make sure its job is to detect and divert copies of new inbox messages to your computer.

• Use a USB dongle for the SIM. When plugged into computer, then you're receiving messages directly to your computer without the phone being involved.

Long version

Rather than command line tools, you're better off making an actual app (via Android SDK) that checks for received messages and forwards some data to you (eg: via email, or sockets, or however you like). Also "some data" meaning either a full copy of the message itself, or just sends feedback of [in-app]message analysis (eg: number of images detected, the hex printout of image bytes and so on).

Looking at Android's SmsManager API it even tells you:

For information about how to behave as the default SMS app on Android 4.4 (API level 19) and higher, see Telephony.

Also look at that API's downloadMultimediaMessage command. It's doing what you need. Telephony page has the information and links to start, but independent blog articles and tutorials (one such example) about this topic are out there too.

Anyways, onto your post...

(1)

"I just want to download the message to a file, without the phone processing it, as it could contain malware"

How do you imagine "without the phone processing it" to work? The phone holds the sim that your operator (via a service centre) will forward messages to, after receiving from sender's own provider's service centre. You and curl are out of this loop. You'll only know of a text when your SIM receives it and the phone OS alerts you.

Technically the phone has processed this message, you just haven't opened it yet.

(2)

"How can I download the MMS file from shell command line or an external browser?"

You have to download that entire mmssms.db file and extract the specific message from it. You treat the .db like any other online database (eg: using SQL/PHP type queries, etc).

See this tutorial for useful advice : http://cheeky4n6monkey.blogspot.co.uk/2013/02/

An alternative for future incoming messages is to just get a (USB) SIM dongle that takes your card. Once plugged into the computer it can receive/send messages since the SIM is live/active inside the dongle (as proxy of phone).

The dongles come with own software (example image of such) for managing web connections and read/write SMS/MMS messages. It's like just having SIM working not in phone but on desktop.