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« Return to Thread: [Telnet] how to determine the prompt?
Re: [Telnet] how to determine the prompt?
by Uwe Fischer-4
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Hello Sebb,
maybe we misunderstood one another...
I was talking about the telnet client example, where the input stream is read as long as a defined "prompt" character is found.
E.g., http://www.informit.com/guides/content.aspx?g=java&seqNum=40
In this example a command like 'ls -l > output.txt' would not be handled properly (of course only if ">" is defined to be the prompt too).
I hope I do not confuse you. Actually I'm just looking for another way to find out when a command has been executed. Isn't the telnet standard offering anything like this? I mean, does the client get some kind of status about the remote machine (something like "busy" or "waiting for command" or similar).
Cheers,
Uwe
> On 03/06/2008, Uwe Fischer <mistuwefischer@...> wrote:
> > Hi Sebb,
> >
> > your idea to change the prompt sounds good. However, how would I identify the very first appearance of the prompt in order to change it? Also, is this (changing the prompt) possible for Windows based telnet servers aswell?
> >
>
> It's not the telnet server that provides the prompt, it's the
> application you are talking to, in that case presumably DOS.
>
> You either need to know what the prompt is in advance, or wait for a timeout.
>
> As I wrote before: how does a human know the system is ready for input?
>
> > Concerning your question, the problem with output redirection is that the program would stop reading from the input stream, due to the appearance of ">" which would indicate that the prompt has been reached. AFAIK.
>
> That does not make sense to me.
>
> If you telnet to a Unix system and issue the command:
>
> ls -l >list.txt
>
> the shell prompt will be issued as soon as the ls program has finished.
>
> > Cheers,
> > Uwe
> >
> >
> >
> > > -----Ursprüngliche Nachricht-----
> > > Von: "sebb" <sebbaz@...>
> > > Gesendet: 03.06.08 14:40:16
> >
> > > An: "Commons Users List" <user@...>
> > > Betreff: Re: [Telnet] how to determine the prompt?
> >
> >
> > > On 03/06/2008, Uwe Fischer <mistuwefischer@...> wrote:
> > > > Hello Pierre,
> > > >
> > > > thanks for your answer.
> > > > Yes, I did what you mention. But it's not "really" solving my issue. The problem I face is that the devices I attach to can have the "#" or ">" characters maintained in a user welcome messages when logging in. E.g., the following welcome message is displayed when logging on to the device:
> > > > ############################################
> > > > Welcome at "hostname". In case of any issues contact Uwe
> > > > ############################################
> > > >
> > > > How can one distinguish the "#" character when used in a comment and when used to indicate the prompt?
> > > >
> > >
> > > Can you set the prompt to a string that is not likely to be seen elsewhere?
> > > Maybe even include a control character such as ^G (bell).
> > >
> > > If not, you are probably going to have to use timeouts to decide when
> > > output has finished.
> > >
> > > > Another problem could occur when somebody would redirect stdout of a Unix system to a file, e.g.:
> > > > ls -l > output_list.txt
> > > >
> > > > Any ideas?
> > >
> > > How would a human know when output has finished?
> > >
> > > > Thanks and best regards,
> > > > Uwe
> > > >
> > > >
> > > > > -----Ursprüngliche Nachricht-----
> > > > > Von: "Pierre Brico" <pierre.brico@...>
> > > > > Gesendet: 03.06.08 11:11:37
> > > > > An: "Commons Users List" <user@...>
> > > > > Betreff: Re: [Telnet] how to determine the prompt?
> > > >
> > > >
> > > >
> > > > > Hello Uwe,
> > > > >
> > > > > Did you try to change the command prompt before executing the command. You
> > > > > just should send commands to the shell like this:
> > > > >
> > > > > PS1="#>"
> > > > > export PS1
> > > > >
> > > > > And you will get the "#>" as prompt.
> > > > >
> > > > > Pierre
> > > > >
> > > > > On Tue, Jun 3, 2008 at 10:50 AM, Uwe Fischer <mistuwefischer@...> wrote:
> > > > >
> > > > > > Hello all,
> > > > > >
> > > > > > I'm looking for a solution to a problem that bothers me for quite some time
> > > > > > now and I hope somebody here can help me out.
> > > > > > I'm using the telnet api to connect to various systems, which works fine.
> > > > > > The problem I face is, how can I determine that a command has run to its
> > > > > > end if there is no static "prompt" character like "#" or ">", but
> > > > > > dynamically changing prompt characters?
> > > > > >
> > > > > > I have read through the Telnet specification but couldn't find anything
> > > > > > that deals with this kind of problem. But surely there must be a solution to
> > > > > > this. I have found another thread in this mailing list concerning a similar
> > > > > > issue, posted by: Anthony Webster Thu, 28 Feb 2008 10:54:35 GMT.
> > > > > > Unfortunately none has answered it yet.
> > > > > >
> > > > > > Thanking in advance,
> > > > > > U.F.
> > > > > >
> > > > > >
> > > > > > ______________________________________________________________
> > > > > > Jeden Monat 1 hochkarätiger maxdome-Blockbuster GRATIS!
> > > > > > Exklusiv für alle WEB.DE Nutzer. http://www.blockbuster.web.de
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> > > > > >
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> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > _______________________________________________________________________
> > > > Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage
> > > > kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220
> > > >
> > > >
> > > >
> > > > ---------------------------------------------------------------------
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> > > > For additional commands, e-mail: user-help@...
> > > >
> > > >
> > >
> > > ---------------------------------------------------------------------
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> > >
> >
> >
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> >
> >
>
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>
>
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maybe we misunderstood one another...
I was talking about the telnet client example, where the input stream is read as long as a defined "prompt" character is found.
E.g., http://www.informit.com/guides/content.aspx?g=java&seqNum=40
In this example a command like 'ls -l > output.txt' would not be handled properly (of course only if ">" is defined to be the prompt too).
I hope I do not confuse you. Actually I'm just looking for another way to find out when a command has been executed. Isn't the telnet standard offering anything like this? I mean, does the client get some kind of status about the remote machine (something like "busy" or "waiting for command" or similar).
Cheers,
Uwe
> On 03/06/2008, Uwe Fischer <mistuwefischer@...> wrote:
> > Hi Sebb,
> >
> > your idea to change the prompt sounds good. However, how would I identify the very first appearance of the prompt in order to change it? Also, is this (changing the prompt) possible for Windows based telnet servers aswell?
> >
>
> It's not the telnet server that provides the prompt, it's the
> application you are talking to, in that case presumably DOS.
>
> You either need to know what the prompt is in advance, or wait for a timeout.
>
> As I wrote before: how does a human know the system is ready for input?
>
> > Concerning your question, the problem with output redirection is that the program would stop reading from the input stream, due to the appearance of ">" which would indicate that the prompt has been reached. AFAIK.
>
> That does not make sense to me.
>
> If you telnet to a Unix system and issue the command:
>
> ls -l >list.txt
>
> the shell prompt will be issued as soon as the ls program has finished.
>
> > Cheers,
> > Uwe
> >
> >
> >
> > > -----Ursprüngliche Nachricht-----
> > > Von: "sebb" <sebbaz@...>
> > > Gesendet: 03.06.08 14:40:16
> >
> > > An: "Commons Users List" <user@...>
> > > Betreff: Re: [Telnet] how to determine the prompt?
> >
> >
> > > On 03/06/2008, Uwe Fischer <mistuwefischer@...> wrote:
> > > > Hello Pierre,
> > > >
> > > > thanks for your answer.
> > > > Yes, I did what you mention. But it's not "really" solving my issue. The problem I face is that the devices I attach to can have the "#" or ">" characters maintained in a user welcome messages when logging in. E.g., the following welcome message is displayed when logging on to the device:
> > > > ############################################
> > > > Welcome at "hostname". In case of any issues contact Uwe
> > > > ############################################
> > > >
> > > > How can one distinguish the "#" character when used in a comment and when used to indicate the prompt?
> > > >
> > >
> > > Can you set the prompt to a string that is not likely to be seen elsewhere?
> > > Maybe even include a control character such as ^G (bell).
> > >
> > > If not, you are probably going to have to use timeouts to decide when
> > > output has finished.
> > >
> > > > Another problem could occur when somebody would redirect stdout of a Unix system to a file, e.g.:
> > > > ls -l > output_list.txt
> > > >
> > > > Any ideas?
> > >
> > > How would a human know when output has finished?
> > >
> > > > Thanks and best regards,
> > > > Uwe
> > > >
> > > >
> > > > > -----Ursprüngliche Nachricht-----
> > > > > Von: "Pierre Brico" <pierre.brico@...>
> > > > > Gesendet: 03.06.08 11:11:37
> > > > > An: "Commons Users List" <user@...>
> > > > > Betreff: Re: [Telnet] how to determine the prompt?
> > > >
> > > >
> > > >
> > > > > Hello Uwe,
> > > > >
> > > > > Did you try to change the command prompt before executing the command. You
> > > > > just should send commands to the shell like this:
> > > > >
> > > > > PS1="#>"
> > > > > export PS1
> > > > >
> > > > > And you will get the "#>" as prompt.
> > > > >
> > > > > Pierre
> > > > >
> > > > > On Tue, Jun 3, 2008 at 10:50 AM, Uwe Fischer <mistuwefischer@...> wrote:
> > > > >
> > > > > > Hello all,
> > > > > >
> > > > > > I'm looking for a solution to a problem that bothers me for quite some time
> > > > > > now and I hope somebody here can help me out.
> > > > > > I'm using the telnet api to connect to various systems, which works fine.
> > > > > > The problem I face is, how can I determine that a command has run to its
> > > > > > end if there is no static "prompt" character like "#" or ">", but
> > > > > > dynamically changing prompt characters?
> > > > > >
> > > > > > I have read through the Telnet specification but couldn't find anything
> > > > > > that deals with this kind of problem. But surely there must be a solution to
> > > > > > this. I have found another thread in this mailing list concerning a similar
> > > > > > issue, posted by: Anthony Webster Thu, 28 Feb 2008 10:54:35 GMT.
> > > > > > Unfortunately none has answered it yet.
> > > > > >
> > > > > > Thanking in advance,
> > > > > > U.F.
> > > > > >
> > > > > >
> > > > > > ______________________________________________________________
> > > > > > Jeden Monat 1 hochkarätiger maxdome-Blockbuster GRATIS!
> > > > > > Exklusiv für alle WEB.DE Nutzer. http://www.blockbuster.web.de
> > > > > >
> > > > > >
> > > > > > ---------------------------------------------------------------------
> > > > > > To unsubscribe, e-mail: user-unsubscribe@...
> > > > > > For additional commands, e-mail: user-help@...
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > _______________________________________________________________________
> > > > Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage
> > > > kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220
> > > >
> > > >
> > > >
> > > > ---------------------------------------------------------------------
> > > > To unsubscribe, e-mail: user-unsubscribe@...
> > > > For additional commands, e-mail: user-help@...
> > > >
> > > >
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: user-unsubscribe@...
> > > For additional commands, e-mail: user-help@...
> > >
> > >
> >
> >
> > _______________________________________________________________________
> >
> > EINE FÜR ALLE: die kostenlose WEB.DE-Plattform für Freunde und Deine
> > Homepage mit eigenem Namen. Jetzt starten! http://unddu.de/?kid=kid@mf2
> >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: user-unsubscribe@...
> > For additional commands, e-mail: user-help@...
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@...
> For additional commands, e-mail: user-help@...
>
>
_______________________________________________________________
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http://www.produkte.web.de/messenger/?did=3016
---------------------------------------------------------------------
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