expectperl-discuss

[Expectperl-discuss] expect output split into pieces

[Jason G. <JG...@cw...>]

Hello,

Here is the problem I am having:

I use expect to spawn an SSH session to a cisco router and run the command =
'show arp', which sends a lot of data back.  example:

gw>show arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
Internet  XX.XX.97.28           171   XXXX.c525.d4c3  ARPA   Vlan122
Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
... (there are thousands of lines sent back)

The problem I get is that expect seems to process this data in chunks.  =
For example, it will process:

Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
Internet  XX.XX.97.28           171   XXXX.c5

where it will pull out the data correctly for the first line, but will not =
match the second line since it is incomplete.  Then, it processes the next =
chunk.  example:

25.d4c3  ARPA   Vlan122
Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124

where it will not pull the data correctly for the first line (incomplete), =
but will pull the correct data for the second line.

I have used the TCL expect before and it does the same thing so I know it =
is not a bug.  I think there is just a gap in my understanding of how =
expect processes the data that is sent back from spawned processes.

Is there a way to make expect deal with all of the data as one big chunk, =
rather than processing it in pieces?  I hope someone can explain how this =
works.



--Jason

Re: [Expectperl-discuss] expect output split into pieces

[Ken I. <fn...@ua...>]

On Thu, May 17, 2007 at 11:53:52AM -0700, Jason Gerdes wrote:
> Hello,
> 
> Here is the problem I am having:
> 
> I use expect to spawn an SSH session to a cisco router and run the
> command 'show arp', which sends a lot of data back.  example:
> 
> gw>show arp
> Protocol  Address          Age (min)  Hardware Addr   Type   Interface
> Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
> Internet  XX.XX.97.28           171   XXXX.c525.d4c3  ARPA   Vlan122
> Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
> ... (there are thousands of lines sent back)
> 
> The problem I get is that expect seems to process this data in chunks.
> For example, it will process:
> 
> Protocol  Address          Age (min)  Hardware Addr   Type   Interface
> Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
> Internet  XX.XX.97.28           171   XXXX.c5
> 
> where it will pull out the data correctly for the first line, but will
> not match the second line since it is incomplete.  Then, it processes
> the next chunk.  example:
> 
> 25.d4c3  ARPA   Vlan122
> Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
> 
> where it will not pull the data correctly for the first line
> (incomplete), but will pull the correct data for the second line.
> 
> I have used the TCL expect before and it does the same thing so I know
> it is not a bug.  I think there is just a gap in my understanding of
> how expect processes the data that is sent back from spawned processes.
> 
> Is there a way to make expect deal with all of the data as one big
> chunk, rather than processing it in pieces?  I hope someone can explain
> how this works.

If you "expect" some string or pattern that appears only after the
desired output is complete, e.g., perhaps the command prompt "gw>",
everything ought to be found in the before() method.

-- 
Ken Irving

Re: [Expectperl-discuss] expect output split into pieces

[Matt Z. <mzagrabe@d.umn.edu>]

> Is there a way to make expect deal with all of the data as one big chunk,=
 rather than processing it in pieces?  I hope someone can explain how this =
works.

not to my knowledge, though a work-around that i have used is to write
everything to a buffer (continually appending the data that expect
returns). next, split'ing the data in that scalar (buffer) into an array
of lines. finally, doing a 'foreach' on the array of lines and
processing as i normally would.

--=20
Matt Zagrabelny - mzagrabe@d.umn.edu - (218) 726 8844
University of Minnesota Duluth
Information Technology Systems & Services
PGP key 1024D/84E22DA2 2005-11-07
Fingerprint: 78F9 18B3 EF58 56F5 FC85  C5CA 53E7 887F 84E2 2DA2

He is not a fool who gives up what he cannot keep to gain what he cannot
lose.
-Jim Elliot

Re: [Expectperl-discuss] expect output split into pieces

[Jason G. <JG...@cw...>]

Thanks to both who answered this question.  I was able to use both of your =
suggestions and my script is working now.  Thanks a lot!!



--Jason

>>> Jason Gerdes <JG...@cw...> 5/17/2007 11:53 AM >>>
Hello,

Here is the problem I am having:

I use expect to spawn an SSH session to a cisco router and run the command =
'show arp', which sends a lot of data back.  example:

gw>show arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
Internet  XX.XX.97.28           171   XXXX.c525.d4c3  ARPA   Vlan122
Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
... (there are thousands of lines sent back)

The problem I get is that expect seems to process this data in chunks.  =
For example, it will process:

Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
Internet  XX.XX.97.28           171   XXXX.c5

where it will pull out the data correctly for the first line, but will not =
match the second line since it is incomplete.  Then, it processes the next =
chunk.  example:

25.d4c3  ARPA   Vlan122
Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124

where it will not pull the data correctly for the first line (incomplete), =
but will pull the correct data for the second line.

I have used the TCL expect before and it does the same thing so I know it =
is not a bug.  I think there is just a gap in my understanding of how =
expect processes the data that is sent back from spawned processes.

Is there a way to make expect deal with all of the data as one big chunk, =
rather than processing it in pieces?  I hope someone can explain how this =
works.



--Jason


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Re: [Expectperl-discuss] expect output split into pieces

[Roland G. <rgi...@cp...>]

how about adjusting your regex to deal with one complete line after another?
something like "Internet.*\n"?

hope this helps,
roland

On 5/17/07, Jason Gerdes <JG...@cw...> wrote:
> Hello,
>
> Here is the problem I am having:
>
> I use expect to spawn an SSH session to a cisco router and run the command 'show arp', which sends a lot of data back.  example:
>
> gw>show arp
> Protocol  Address          Age (min)  Hardware Addr   Type   Interface
> Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
> Internet  XX.XX.97.28           171   XXXX.c525.d4c3  ARPA   Vlan122
> Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
> ... (there are thousands of lines sent back)
>
> The problem I get is that expect seems to process this data in chunks.  For example, it will process:
>
> Protocol  Address          Age (min)  Hardware Addr   Type   Interface
> Internet  XX.XX.108.17            0   XXXX.319f.c3d9  ARPA   Vlan133
> Internet  XX.XX.97.28           171   XXXX.c5
>
> where it will pull out the data correctly for the first line, but will not match the second line since it is incomplete.  Then, it processes the next chunk.  example:
>
> 25.d4c3  ARPA   Vlan122
> Internet  XX.XX.99.30            41   XXXX.420c.e73f  ARPA   Vlan124
>
> where it will not pull the data correctly for the first line (incomplete), but will pull the correct data for the second line.
>
> I have used the TCL expect before and it does the same thing so I know it is not a bug.  I think there is just a gap in my understanding of how expect processes the data that is sent back from spawned processes.
>
> Is there a way to make expect deal with all of the data as one big chunk, rather than processing it in pieces?  I hope someone can explain how this works.
>
>
>
> --Jason
>
>
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