apt-key:tldr:fa624

The apt-key command is used in Ubuntu and other Debian-based systems to manage repositories and their associated GPG (GNU Privacy Guard) keys. The adv argument is short for "advanced" and indicates that advanced key management operations will be performed.

Here's a breakdown of the provided command:

apt-key adv --keyserver ${pgp-mit-edu} --recv ${KEYID}

1. apt-key: Invokes the apt-key command for managing GPG keys.
2. adv: Specifies that advanced key management operations will be performed.
3. --keyserver ${pgp-mit-edu}: Specifies the keyserver to use when retrieving the GPG key. ${pgp-mit-edu} is a placeholder for the actual keyserver URL. In this case, it seems that the keyserver is expected to be pgp.mit.edu.
4. --recv ${KEYID}: Specifies that the specified GPG key identifier (${KEYID} placeholder) should be retrieved from the keyserver. The specified GPG key will be downloaded and imported into the local keyring to verify the authenticity and integrity of packages from that repository.

In summary, this command is used to retrieve a specific GPG key from a specified keyserver and import it into the apt package manager's keyring, allowing the system to verify the authenticity of packages from a particular repository.