你得编译客户端，然后用cli_wallet, list_keys()

Dumps all private keys owned by the wallet.

The keys are printed in WIF format. You can import these keys into another
wallet using 'import_key()'

Returns
    a map containing the private keys, indexed by their public key

更详细的用法可以参考这里：
https://steemit.com/steemhelp/@hannixx42/cliwallet-commands-v0

个人 permission 页有几个 show 链接，点开就是显示私钥。
注意分 owner active posting memo 四个私钥，owner是主私钥可以改其他几个，active是转账、power up用的，posting是发帖顶贴用的，memo是加密私信用的（目前暂时不提供这个功能）。