SSH Cheat Sheet

[thedougd]

Favorites for scripting including the ability to run any command or script on the remote.

  ssh remotehost reboot

Heredoc syntax also works:

  ssh remotehost <<'EOF'
  ls
  cat /etc/passwd
  reboot
  EOF

[rollulus]

My favorite Konami code level of cheat: ssh escape sequences. On a new line: ~. to terminate a connection that’s stuck. Or ~? for more help.

[LeoPanthera]

Since it's sometimes unclear whether you are on a new line in a stuck terminal, I find it simpler to remember the sequence as [Return][~][.]

[thedougd]

Great one! This needs communicated more broadly. I spent too many years of my life killing terminals because of a dead ssh connection.

[danuker]

Better yet, use Mosh.

https://mosh.org/

[marcobehler]

Thanks, indeed a great one! Will put it in the article.

[acatton]

PSA: scp is deprecated.[1] Please use sftp.[2]

[1] https://lwn.net/Articles/835962/

[2] https://man.openbsd.org/sftp.1

[neurostimulant]

scp uses sftp protocol by default since v8.8. You'll need to pass `-O` parameter to explicitly use the legacy scp protocol if you still need it for backward compatibility reason.

[dhsysusbsjsi]

As an scp user, this article was not a great advertisement for sftp. It listed a whole host of problems that don't apply to me, then finished with:

"[sftp] disadvantage is a much less friendly user experience, especially in cases where one simply wants to type a command and see files move."

I just want to copy a file. I'll keep using scp.

[LanternLight83]

IIRC, wasn't scp going to be rewritten in terms of SFTP behind the scenes?

[thefilmore]

The scp command uses the SFTP protocol since OpenSSH 9.

[marcobehler]

Didn't know that! Thank you, will update the post.

[peppermint_tea]

a few more examples on ssh tunnels : https://cloudbase.200013.net/doc/linux/ssh/ssh_tunelling.htm...

[tommica]

That is a useful guide - I used to do that with Spotify long time ago, when I was living in a different country

[kaliszad]

I like how this guide also takes Windows into account, it has some unique challenges.

I have written some notes especially on SSHFS (also for Windows!) and tunnels with SSH (e.g. SOCKS proxy) as an OrgPage: https://www.orgpad.com/s/wRIx3rNLZ6y These tricks saved my bacon so many times already. Most of it can be used with the FUDO PAM jump host appliance (https://fudosecurity.com/fudo-pam/) that is based on FreeBSD and one of the developers spoke about it and other things on https://www.bsdnow.tv/ I think. Some of it works with OpenWRT's Dropbear nicely as well.

[qwertox]

I also find `ssh-copy-id` useful.

[Daviey]

I like the idea for multiple Github accounts, but I have concerns over the suggestion:

``` Host github-work.com .. Host github-personal.com ```

Getting in the habit of using a fake FQDN (which right now aren't registered) feels pretty risky.

[cameronperot]

This is a nifty trick, but I recently had an issue where it would offer my other keys even with IdentitiesOnly yes specified in ~/.ssh/config. I found a solution [1], but it's not the most elegant.

[1] https://superuser.com/a/859719

[dandanua]

The most annoying "feature" of ssh for me is the discrepancy between public keys presentations. How I suppose to verify fingerprint of a new server if it uses a different presentation in the keys file?

[LeoPanthera]

> ssh-keygen -t rsa -b 4096 -C "[email protected]"

Is there any evidence that 2048 bit RSA keys are insufficient?

4096 bit keys are absolutely huge. I don't know if working with them is also slower, but I would guess so.