Your SSH agent is running and you want to see the fingerprints of the identities it is currently holding in memory. Type the complete command.
LPIC-1 Exam 102-500, objective 110. Security medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
Answer
Type the answer.
Accepted answer
ssh-add -l
Case sensitive — Linux is, and grading LS as ls would teach a falsehood.
Why
ssh-add -l lists the fingerprint of every private key the running agent currently holds; -L prints the full public keys instead of fingerprints. `ssh-add` with no arguments loads the default keys from ~/.ssh (id_rsa, id_ecdsa, id_ed25519 and so on), `ssh-add path/to/key` loads a named key, `ssh-add -d` removes one identity and `ssh-add -D` removes them all. Every one of these commands talks to the agent through the socket named by SSH_AUTH_SOCK, so if that variable is unset you get 'Could not open a connection to your authentication agent'.
Where this comes from
- Cited
- LPI exam objective 110.3
- What it says
- Use ssh-agent and ssh-add to hold decrypted private keys for reuse.
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 110 and space the ones you get wrong.
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