diff --git a/README.md b/README.md index 6ae5750..3ca82e1 100644 --- a/README.md +++ b/README.md @@ -10,7 +10,7 @@ pairing with smart people at Hashrocket. For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186). -_1292 TILs and counting..._ +_1293 TILs and counting..._ --- @@ -1219,6 +1219,7 @@ _1292 TILs and counting..._ - [Change To That New Directory](unix/change-to-that-new-directory.md) - [Check If A Port Is In Use](unix/check-if-a-port-is-in-use.md) - [Check If Command Is Executable Before Using](unix/check-if-command-is-executable-before-using.md) +- [Check SSH Key Fingerprints Of Known Hosts](unix/check-ssh-key-fingerprints-of-known-hosts.md) - [Check The Current Working Directory](unix/check-the-current-working-directory.md) - [Clear The Screen](unix/clear-the-screen.md) - [Command Line Length Limitations](unix/command-line-length-limitations.md) diff --git a/unix/check-ssh-key-fingerprints-of-known-hosts.md b/unix/check-ssh-key-fingerprints-of-known-hosts.md new file mode 100644 index 0000000..924ea44 --- /dev/null +++ b/unix/check-ssh-key-fingerprints-of-known-hosts.md @@ -0,0 +1,31 @@ +# Check SSH Key Fingerprints Of Known Hosts + +The `ssh-keygen` utility can do a bunch of things related to SSH keys including +generating key pairs, removing a key, and even showing the fingerprints for a +public keys file. + +After [the recent GitHub SSH key +rotation](https://github.blog/2023-03-23-we-updated-our-rsa-ssh-host-key/), I +wanted to check that the key I had added produced a fingerprint matching what +they described in the article. + +The `-l` flag will list the fingerprints and the `-f` flag allows you to +specify what file it processes when doing that. + +```bash +ssh-keygen -lf ~/.ssh/known_hosts +``` + +I have a bunch of known hosts, so I can narrow it down to just the GitHub entry +like so. + +```bash +ssh-keygen -lf ~/.ssh/known_hosts | grep github.com +3072 SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s github.com (RSA) +``` + +And [it matches what GitHub +lists](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/githubs-ssh-key-fingerprints), +so I'm good to go. + +See `man ssh-keygen` for more details.