Generate an Ed25519 SSH key pair at ~/.ssh/id_ed25519 without overwriting an existing file.
Which command is appropriate?
ssh-keygen -t ed25519 -f PATH selects the key type and output path. Confirm overwrite behavior separately.
Detailed explanation
ssh-add -t ed25519 ~/.ssh/id_ed25519Correct. It generates an Ed25519 key pair at the selected path.
Correct. It generates an Ed25519 key pair at the selected path.
ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519Incorrect. ssh-add registers an existing private key with an agent.
Incorrect. ssh-add registers an existing private key with an agent.
ssh -t ed25519 -f ~/.ssh/id_ed25519Incorrect. ssh -t allocates a pseudo-terminal, not a key type.
Incorrect. ssh -t allocates a pseudo-terminal, not a key type.
gpg --generate-key ed25519 ~/.ssh/id_ed25519Incorrect. GnuPG key generation is a different format and command.
Incorrect. GnuPG key generation is a different format and command.
Try it yourself
An example you can run in a temporary verification environment.
tmp=$(mktemp -d); ssh-keygen -q -t ed25519 -N '' -f "$tmp/id_ed25519"; test -f "$tmp/id_ed25519.pub" && printf 'public key exists\n'; rm -rf "$tmp"Expected result
public key existsKey points
- ssh-keygen generates
- -t selects key type
- -f selects output path
Notes
- Environment: OpenSSH client / 一時ディレクトリ
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.