initializing/unlocking key explicitely with gpg-agent

[Michael Richardson]

<#part sign=pgpmime>

Werner Koch <wk at gnupg.org> wrote:
    > There are two or there ways ways: $ gpg-connect-agent
    >> /let passwd abc /definq PASSPHRASE passwd preset_passphrase --inquire
    >> example-cache -1
    > S INQUIRE_MAXLEN 480 INQUIRE PASSPHRASE OK
    >> get_passphrase example-cache X X X
    > OK 31323334
    >> # Second version using a hexified passphrase preset_passphrase
    >> example-cache -1 616263
    > OK
    >> get_passphrase example-cache X X X
    > OK 616263
    >>

    > There is also a tool which implements the above: $
    > /usr/local/libexec/gpg-preset-passphrase -c -P ABC example-cache $
    > gpg-connect-agent 'get_passphrase example-cache X X X' /bye OK 414243

I see, it's in /usr/lib/gnupg/gpg-preset-passphrase  on debian packages.
Not sure why it's not in the $PATH.  Would patches that made it prompt, and
turn off echo if isatty() be welcome?

Thank you.