How to create a RPC wallet from the console?

Question

How do I create a wallet to simply confirm receipt?

nicholas@mordor:~/monero_console$ 
nicholas@mordor:~/monero_console$ ll
total 461
drwxrwxr-x  3 nicholas nicholas      5 Dec 27 10:04 ./
drwxr-x--- 32 nicholas nicholas    130 Dec 27 07:04 ../
drwxrwxr-x  3 nicholas nicholas      3 Dec 26 18:06 monero-linux-x64-v0.17.3.0/
-rw-------  1 nicholas nicholas 410254 Dec 27 09:01 mordor
-rw-------  1 nicholas nicholas   1587 Dec 26 20:45 mordor.keys
nicholas@mordor:~/monero_console$ 
nicholas@mordor:~/monero_console$ ./monero-linux-x64-v0.17.3.0/monero-x86_64-linux-gnu-v0.17.3.0/monero-wallet-cli --generate-from-view-key mordor.keys
This is the command line monero wallet. It needs to connect to a monero
daemon to work correctly.
WARNING: Do not reuse your Monero keys on another fork, UNLESS this fork has key reuse mitigations built in. Doing so will harm your privacy.

Monero 'Oxygen Orion' (v0.17.3.0-release)
Logging to ./monero-linux-x64-v0.17.3.0/monero-x86_64-linux-gnu-v0.17.3.0/monero-wallet-cli.log
Standard address: 42mEMYePTEy5rQJJWxEFBnRusHgcRZLxiD9jzu1vjb3m7kSYtUYrPJqDga8XyQ9KsX3td7o4gtSzTfmw8ftA3voFKMjtGJu
Secret view key: <secret key here>

Enter a new password for the wallet: 
Confirm password: 
Error: failed to generate new wallet: file already exists "mordor"
nicholas@mordor:~/monero_console$ 

Answer 1

monero-wallet-cli and monero-wallet-rpc are just different programs to work with a wallet file; they offer the same functionality just that one is an interactive CLI and the other is an RPC server.

So, they both have functionality to create wallet files (the CLI's --generate-from-view-key being one of many ways). See monero-wallet-cli --help for others, and wallet-rpc.html for the monero-wallet-rpc docs.

Now, specifically to the way you tried in the question, it's easy to see you tried to create a wallet that already existed, hence the error:

Error: failed to generate new wallet: file already exists "mordor"

Note that the --generate-from-view-key argument is actually expecting a wallet name, not a keys file, and when executed it will prompt you for various things, including the view key (not a file, but the actual hex encoded key).

It looks like you are trying to create a view only wallet from a full wallet's keys file, which is incorrect here. Assuming you have a wallet named "mordor" in the current directory, you could copy the key printed by:

monero-wallet-cli --wallet-file mordor viewkey

Then run:

monero-wallet-cli --generate-from-view-key mordorview

Once you've answered the questions, you'll have new mordorview and mordorview.keys files (which are your new view-only wallet file and keys).