Summarize SSH Authorized Key Types

You need to count SSH key algorithms used in authorized_keys files.

Command

find home -path '*/.ssh/authorized_keys' -exec awk '{print $1}' {} + | sort | uniq -c | sort -nr

Before you run this

Risk: safe. Do not delete RSA keys solely because they appear here; confirm policy, fingerprint, owner, and compatibility first.

Expected output

A count-sorted list of authorized SSH key types.

System impact

Nothing changes. The command reads authorized_keys files and counts the first field, which is the key type.

Recovery / rollback: no state is changed.

When to use it

Use during SSH access reviews when you need to spot legacy key types before planning cleanup.

When not to use it

Do not delete RSA keys solely because they appear here; confirm policy, fingerprint, owner, and compatibility first.

Watch this command run

Example output from a temporary Linux lab

This example uses disposable sample files and sanitized output so you can inspect the shape of the result before touching a real system.

demo@lab:~$

$ find home -path '*/ssh-keys/authorized_keys' -exec awk '{print FILENAME, $1}' {} +

home/deploy/ssh-keys/authorized_keys ssh-ed25519
home/bob/ssh-keys/authorized_keys ssh-rsa
home/alice/ssh-keys/authorized_keys ssh-ed25519
home/alice/ssh-keys/authorized_keys ssh-rsa

$ find home -path '*/ssh-keys/authorized_keys' -exec awk '{print $1}' {} + | sort | uniq -c | sort -nr

      2 ssh-rsa
      2 ssh-ed25519

View reproducible demo details

This page shows the sanitized shell transcript and the setup steps needed to reproduce the example.