Command line `prove` command doesn't allow unlocking private key

I've just installed keybase and I'm trying it out, I've had a browse through the issues, but this doesn't seem to be reported. Sorry if it is.

I've generated a key, and pushed the public key (but not the private key) to the server.

When I try on the command-line `keybase prove github`, it doesn't allow input of the passphrase to unlock the secret key

```
~ keybase prove github
Your username on GitHub: mountainpenguin

You need a passphrase to unlock the secret key for
user: "keybase.io/mountainpenguin "
4096-bit RSA key, ID 3C02E***********, created 2014-04-10
(subkey on main key ID D75433**********)

```

Someone suggested that it may be trying to open a dialog, however this is running on my server so it will not be able to do so (at least not visibly over SSH).

```
~ keybase version
keybase (keybase.io CLI) v0.2.19
- node.js v0.10.21
- gpg (GnuPG) 2.0.22
- libgcrypt 1.5.3
Identifies as: 'keybase.io node.js client v0.2.19 linux'
```

```
~ node --version
v0.10.21
```

```
~ gpg --version
gpg (GnuPG) 2.0.22
libgcrypt 1.5.3
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, ELG, DSA, ?, ?
Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
CAMELLIA128, CAMELLIA192, CAMELLIA256
Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
Compression: Uncompressed, ZIP, ZLIB, BZIP2
```

Running on Gentoo Linux x86_64, kernel version 3.8.13,

Reproduce `keybase prove github` in the reported non-graphical SSH environment, using the command-line prove entry point and the listed Keybase, Node.js, and GnuPG versions as context. Trace how the CLI requests the secret-key passphrase and make completion possible without a visible dialog; verify that the GitHub proof can proceed after passphrase entry.

Written by the indexing model from the issue text.