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Manuel Jordan
Asked: 2022-12-13 17:32:28 +0800 CST

apt-key command: What is the difference among '--recv-key', '--recv-keys' and '--recv' options?

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For documentation purposes, about the apt-key command in many places I found these two variations:

sudo apt-key adv --keyserver       keyserver.ubuntu.com    --recv-keys PUBKEY
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv      PUBKEY

Observe the difference about the latest option --recv-keys and --recv. About the Ubuntu's official man at jammy apt-key(8) does mention only about:

   adv (deprecated)
       Pass advanced options to gpg. With adv **--recv-key** you can e.g. download key from
       keyservers directly into the trusted set of keys. Note that there are no checks
       performed, so it is easy to completely undermine the apt-secure(8) infrastructure if
       used without care.

And now from above see other option --recv-key (different as --recv-keys - it ends with s)

And at jammy gpg(1) does mention only about:

 --recv-keys keyIDs
        Import the keys with the given keyIDs from a keyserver.

Observation in the mentioned man appears the --recv-key term as content for other options but it does not exist as an option definition itself. ( consider to use the ctrl + f keys to search using the --recv as search term, it because there is a line with the --recv-key term split in 2 lines.)

Question

  • What is the difference among --recv-key, --recv-keys and --recv options?

If exists these 3 options, therefore each one has a specific purpose.

apt

1 Answers

  1. Best Answer

    It's not obvious from the documentation, but gpg is one of those commands where you can pass a unique prefix of an option instead of having to type it out in full. If you had two options such as:

    --some-long-option
--some-other-long-option

    Then any of --some-l, --some-lo, --some-lon, etc. is enough to distinguish it from --some-other-long-option. So, you could use these abbreviated forms instead of always using --some-long-option.

    This is implied by the documentation however, where it says that "the option may not be abbreviated" in gpg.conf (and some other options like --help, --version, etc. cannot be abbreviated either).

    So all three of --recv, --recv-key and --recv-keys are equivalent.

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