user4723: Which command should I use to encrypt a previously unencrypted wallet from the command line? 

user-1: The command is: bitcoin-cli encryptwallet mypassphrase. 
The list with all commands exposed through bitcoind's RPC API can be found here: https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list or can be fetched with the command: bitcoin-cli help. 
It's worth noting that the encryptwallet command will not show up in bitcoin-cli help's results once your wallet is encrypted, instead you will get three new commands: walletlock,
walletpassphrase and walletpassphrasechange.

4723: <p>Which command should I use to encrypt a previously unencrypted wallet from the command line? </p>
 -1: <p>The command is: <code>bitcoin-cli encryptwallet mypassphrase</code>. </p>

<p>The list with all commands exposed through bitcoind's RPC API can be found here: <a href="https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list" rel="noreferrer">https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list</a> or can be fetched with the command: <code>bitcoin-cli help</code>. </p>

<p>It's worth noting that the <code>encryptwallet</code> command will not show up in <code>bitcoin-cli help</code>'s results once your wallet is encrypted, instead you will get three new commands: <code>walletlock</code>,
<code>walletpassphrase</code> and <code>walletpassphrasechange</code>.</p>
