I was curious about proving that ssh key pair match but am having trouble converting my private key:

$ openssl rsa -outform PEM -in ~/.ssh/id_rsa -out id_rsa.pem
Could not read private key from /home/peon/.ssh/id_rsa
$ ls -ld ~/.ssh/id_rsa
-rw------- 1 peon peon 2610 Apr 4 2024 /home/peon/.ssh/id_rsa
$

I use the key all the time for ssh. Does anyone have an idea what’s wrong?