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Sometimes my ssh session in the terminal hangs. How can I exit the ssh session and reconnect?

Kit Sunde
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8 Answers8

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Type ~. (i.e. tilde, period) at the beginning of a line. In other words, press Enter, then ~, then .. (In some languages, you may need to press Shift or ⌥ Option/Alt to enter the ~ character.)

Generally speaking, the ~ character is an escape character in an SSH session when you type it at the beginning of a line. Type Enter then ~? to see the list of escape commands. The most common ones are

  • ~. to terminate the connection
  • ~^Z (press ~ then Ctrl+Z) to suspend the connection and type a command locally (run the command fg to return to the SSH session)

If you want a tilde at the beginning of a line, press ~ twice.

Gilles 'SO- stop being evil'
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  • This works only if you have an ANSI keyboard, I have spanish keyboard and doens't work, in spanish the "tilde" key ~ is made with AltGr + 4. But if I change the keyboard layout to english, and I use Shift + º, then it works! – Johan Alexis Duque Cadena Dec 18 '20 at 11:42
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    @JohanAlexisDuqueCadena I don't know what an “ANSI keyboard” is but I don't think it's relevant. If your tilde key is a dead key (i.e. typing ~ doesn't insert ~ immediately, but typing e.g. ~ then a inserts ã), you may need to type a space after ~ to actually insert a tilde, then type the second character. See also https://apple.stackexchange.com/questions/219603/how-do-i-type-a-tilde-in-spanish-keyboard – Gilles 'SO- stop being evil' Dec 19 '20 at 20:00
  • Works for me with German keyboard layout and Alt Gr + +. – Paul P Mar 12 '21 at 19:47
  • This worked for me in iTerm2 on MacOS. On my US keyboard, I had to type Shift + "~", then ".". I regret taking so many years to look for this answer. – nicbou Feb 07 '23 at 09:54
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If your session is hung and the prompt is no longer responsive you can just kill the Terminal instance. All child processes associated with that instance, including your ssh session, exit.

A more thorough approach, open a new shell (new tab or window), list ssh sessions and send kill signals:

> ps -ef  |grep ssh
501  1332   142   0 20Dec11 ??         0:01.33 /usr/bin/ssh-agent -l
501 57172 57150   0  1:58pm ttys000    0:00.01 grep ssh
501 57139 57133   0  1:57pm ttys002    0:00.03 ssh -i/Users/ian/code/ec2-keys/id_rsa-gsg-keypair [email protected]

> kill 57139

If that doesn't work try:

> kill -9 57139

Don't kill the ssh-agent or sshd Processes.

Or you can open Activity Monitor and search there for sessions and hit the "Quit Process" button for them:

Activity Monitor filtering for ssh sessions

bmike
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Ian C.
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  • +1, this is what I do. Often where I've left a session running, and then either the connection breaks accidentally or I sleep the laptop, it causes ssh to freeze. I open a new console tab and kill the PID of the ssh process (or close the ssh tab and open a new one) – halfer Jan 06 '12 at 00:07
  • Does using the keyboard shortcut work on your Mac without tediously killing the process? – Rafael Bugajewski Jan 18 '13 at 10:57
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    Use ~.. See above. – Snowcrash Apr 04 '19 at 08:16
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All you need to do to exit an ssh session is type exit at the prompt.

Try entering Shift+`+.

daviesgeek
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    It's not accepting user input anymore, it's literally stalled. On Ubuntu there's a keyboard combination that terminates the session that you can use in cases like these. After a while the session will terminate stating broken-pipe but I rather not wait. – Kit Sunde Jan 04 '12 at 19:00
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    @Kit I fixed my answer. Sorry about that. I didn't realize you meant a completely stalled SSH session. – daviesgeek Jan 04 '12 at 19:04
  • I usually just wait for it to timeout. Despite the fact that I know about these commands, I always forget that I can use them to expedite the process of getting my shell back.

    Note @Gilles answer as well, you may have to press Enter/Return once before ~.

    You can learn more in the SSH manpage (a bit over halfway in), and by typing: ~? into an active/connected SSH session, again, you may have to hit enter once before.

     – Jason Salaz Jan 04 '12 at 22:24
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According to the documentation: 

 Supported escape sequences:
 ~.   - terminate connection (and any multiplexed sessions)
 ~B   - send a BREAK to the remote system
 ~C   - open a command line
 ~R   - request rekey
 ~V/v - decrease/increase verbosity (LogLevel)
 ~^Z  - suspend ssh
 ~#   - list forwarded connections
 ~&   - background ssh (when waiting for connections to terminate)
 ~?   - this message
 ~~   - send the escape character by typing it twice
(Note that escapes are only recognized immediately after newline.)
Adam Krawczyk
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1

~. works, although it looks like being totally stuck, stops the ssh connection and you can start it again, but in my keyboard I have to press Alt+~ then space and then .

Hannu
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For me, working with Terminal in macOS Mojave 10.14.6 the only solution was to enter ~ followed by Ctrl-Z as described in this answer: https://apple.stackexchange.com/a/175670/136875

Gregory Cosmo Haun
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From Ian's answer on apple.stackexhange, this is the answer for Mac OS X:

The default escape key for the ssh that ships with OS X the ~ character. You have to enter it immediately after a new line for ssh to respect it. And then the key sequence Control-z is used to suspend and background a task in bash.

So try this key sequence:

Return

~

Control-z

If it works you'll see something like:

myhost.local:~ |ruby-2.2.0|
> ssh someremotehost
Last login: Fri Mar  6 14:15:28 2015 from myhost

someremotehost:~ |ruby-2.2.0|
> ~^Z [suspend ssh]


[1]  + 48895 suspended  ssh myremotehost
John D
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For mac users (new macs).

it's option + N then shift + ; .

Badr Bellaj
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