$ ssh-keygen -lf ~/.ssh/id_rsa.pub
2048 6a:e7:4c:68:96:7e:4c:87:3c:2f:ca:cd:8d:3e:34:5a epriestley@Evan-Priestleys-MacBook-Pro.local (RSA)
$ ssh-keygen -lf nickz.pub
key_read: uudecode AAAAB3NzaC1yc2EAAAADAQABAAABAQDRpZdlHKdROQUuV2McztPWsJkGShHU8QbQJOIOqyXehAZg14mgt3xWlIwG8SI/shSWab37sKMLMBff7r1ZBkc679WclPhY2Tp6IApgz4Js2mtOKV6FFFwZgD2gpAlgVUNocnBXvG5NZtK1OWeADFsFxSMKaUDpoCPL35k6n2Od8xRqdBDYB/V3qX4ZDwEPUUf6RoVZwMT/dwk0TqFCKQ1JUgcLN5K4dhYYH5JDSpvdm0W6eR0yTl2EGnYCjlTNwKLwUq4t3M2SzBFEPTbxwGYe57khEL0IW6Oznl9HZZHewfbeQP/tpiMoJ9B4XdishcZQAjHvtl2twumYc4Q47tQNmnN nickz@pinterest.com
failed
nickz.pub is not a public key file.