Remove invalid key from the known_hosts file for the IP address of a host

ssh-keygen -R `host hostname | cut -d " " -f 4`
Quick shortcut if you know the hostname and want to save yourself one step for looking up the IP address separately.

5
By: flart
2009-09-23 14:58:28

2 Alternatives + Submit Alt

What Others Think

nice! because I always delete the wrong line in the known_hosts file upon key errors, ever since the hostnames started being hashed by default. This is great, although I wonder if this will get each and every instance since the hosts' key may be listed under three different names: (1) the bare hostname, such as "bob", (2) the FQDN, such as "bob.example.com", or (3) the IP address. I'm guessing ssh-keygen just deletes entries corresponding to exactly what the input was.
bwoodacre · 456 weeks ago
@bwoodacre Exactly. You need to run 'ssh-keygen -R' for every instance of the host in the known_hosts file. It's nevertheless more comfortable than editing it by hand IMO :-)
flart · 455 weeks and 6 days ago
Repeat after me: avoid backticks, they're evil ...
assarbad · 330 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands



Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: