[gentoo-user] ssh escape command

[gentoo-user] ssh escape command

[Mick]

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How do you explain this:

I am in a ssh session.  I type "~." to end the session.  The first time it 
says command not found, the second time the escape character is recognised 
and executed, I am logged out.
=========================================
$ ~.
-bash: ~.: command not found
$ Connection to blah.blah.blah. closed.
=========================================
-- 
Regards,
Mick

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Re: [gentoo-user] ssh escape command

[felix]

On Thu, Mar 29, 2007 at 05:10:43PM +0100, Mick wrote:
> How do you explain this:
> 
> I am in a ssh session.  I type "~." to end the session.  The first time it 
> says command not found, the second time the escape character is recognised 
> and executed, I am logged out.
> =========================================
> $ ~.
> -bash: ~.: command not found
> $ Connection to blah.blah.blah. closed.
> =========================================

Don't know about that, but I just found a peculiarity in ssh.  If I
ssh from a to b to c, "~." terminates the a-b session which also
terminates the b-c session of course.  Use "~~." instead to first
terminate the b-c session while leaving a-b intact, but immediately
folloing that with "~." to terminate the a-b session does not work; it
gives "command no found" from bash.  You have to give any other
command in betweenm, even ENTER alone, then the "~." will properly
terminate the a-b session.

This might be what you were seeing, if you had just used "~~." to
terminate a nested session.

-- 
            ... _._. ._ ._. . _._. ._. ___ .__ ._. . .__. ._ .. ._.
     Felix Finch: scarecrow repairman & rocket surgeon / felix@crowfix.com
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I've found a solution to Fermat's Last Theorem but I see I've run out of room o
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Re: [gentoo-user] ssh escape command

[Willie Wong]

On Thu, Mar 29, 2007 at 09:49:35AM -0700, felix@crowfix.com wrote:
> > How do you explain this:
> > 
> > I am in a ssh session.  I type "~." to end the session.  The first time it 
> > says command not found, the second time the escape character is recognised 
> > and executed, I am logged out.
> > =========================================
> > $ ~.
> > -bash: ~.: command not found
> > $ Connection to blah.blah.blah. closed.
> > =========================================
<snip>
> This might be what you were seeing, if you had just used "~~." to
> terminate a nested session.

You are on the right track, but not quite:

>From the man page: the ~ character has to be preceded by a newline to be 
recognized as special. The reason that ~~. followed by ~. does not terminate 
your initial connection is because the first layer of ssh still thinks
you are typing on the same line. Basically the first layer of ssh sees this
sequence "~~.~." and the first two tildes makes it think: ah, this is not 
an escape sequence, and sends the string "~.~." to the remote shell, the 
first two of which gets trapped by the second ssh layer to mean disconnect
and the second two characters is just received by the shell. 

So, most likely the OP was typing something/anything that gave him a empty 
prompt without hitting a newline (hitting ^C, ^Z on a running program or 
just on the shell, typing something and hitting backspace to delete it...)

Incidentally, you shouldn't need to hit the newline before the disconnect
occurs. The minute you actually see the ~ appear on the screen you should 
know that it is not being interpreted as an escape character. 

W
-- 
Willie W. Wong                                      wwong@math.princeton.edu
408 Fine Hall,  Department of Mathematics,  Princeton University,  Princeton
A mathematician's reputation rests on the number of bad proofs he has given.
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Re: [gentoo-user] ssh escape command

[Hans-Werner Hilse]

Hi,

On Thu, 29 Mar 2007 14:38:41 -0400 Willie Wong <wwong@princeton.edu>
wrote:

> So, most likely the OP was typing something/anything that gave him a
> empty prompt without hitting a newline (hitting ^C, ^Z on a running
> program or just on the shell, typing something and hitting backspace
> to delete it...)
> 
> Incidentally, you shouldn't need to hit the newline before the
> disconnect occurs. The minute you actually see the ~ appear on the
> screen you should know that it is not being interpreted as an escape
> character. 

Just to add to the overall confusion: In many cases for non-american
keyboard layouts, "~" is configured as "dead key" in X (in order to
type things like "ñ" and such). For a "~", you effectively have to type
"~",<SPACE>. So my series of keystrokes is almost always:
<CR>,"~",<SPACE>,".". But I only need that when the connection dies,
otherwise I still prefer <CTRL>-D.

-hwh
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