CentOS - Jun 2009 - script help - '3rd last field'

Hi

I need some logic to work out a value for me - this value is _always_ 
the 3rd last field in a string seperated by '.' but the string could be 
5 or 6 fields long, e.g

foo.bar.VALUE.baz.lala

foor.bar.gigi.VALUE.baz.lala

I need to find VALUE - if this were python or something i could do it 
but this has to be in shell -

Any clues?

thanks

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

On Mon, Jun 8, 2009 at 4:29 PM, Tom Brown<tom at ng23.net>
wrote:
> Hi
>
> I need some logic to work out a value for me - this value is _always_
> the 3rd last field in a string seperated by '.' but the string
could be
> 5 or 6 fields long, e.g
>
> foo.bar.VALUE.baz.lala
>
> foor.bar.gigi.VALUE.baz.lala
>
> I need to find VALUE - if this were python or something i could do it
> but this has to be in shell -

awk -F\. {'print $3'}
awk -F\. {'print $5'}
awk -F\. {'print $6'}



-- 
Muhammad Panji
http://sumodirjo.wordpress.com
http://www.kurungsiku.web.id

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

Sehr geehrte Damen und Herren, 

ich bin ab dem 15.06.2009 wieder zur?ck im B?ro.
Bitte wenden Sie sich in dringenden F?llen an Simon Schillings [simon.schillings
at rm-solutions.de]

Viele Gr??e,
Michael Kettel

On Mon, Jun 8, 2009 at 5:29 AM, Tom Brown<tom at ng23.net>
wrote:
> Hi
>
> I need some logic to work out a value for me - this value is _always_
> the 3rd last field in a string seperated by '.' but the string
could be
> 5 or 6 fields long, e.g
>
> foo.bar.VALUE.baz.lala
>
> foor.bar.gigi.VALUE.baz.lala
>
> I need to find VALUE - if this were python or something i could do it
> but this has to be in shell -
>
> Any clues?
>
> thanks
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>
I am pretty sure there is a way in awk to figure out how many fields
you have, then take the total # of fields -3 each time to get the
third last one.  Just heading out the door and off hand can't remember
how it would be done.

Jacques B.

Hi.

   echo foo.bar.VALUE.baz.lala | awk -F. '{ print $(NF-2); }'

-- 
Alex S.<magicboom at gmail.com>



On 08.06.2009 13:29, Tom Brown wrote:
> Hi
>
> I need some logic to work out a value for me - this value is _always_
> the 3rd last field in a string seperated by '.' but the string
could be
> 5 or 6 fields long, e.g
>
> foo.bar.VALUE.baz.lala
>
> foor.bar.gigi.VALUE.baz.lala
>
> I need to find VALUE - if this were python or something i could do it
> but this has to be in shell -
>
> Any clues?
>
> thanks
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

On Mon, 2009-06-08 at 10:29 +0100, Tom Brown wrote:
> Hi
> 
> I need some logic to work out a value for me - this value is _always_ 
> the 3rd last field in a string seperated by '.' but the string
could be
> 5 or 6 fields long, e.g
> 
> foo.bar.VALUE.baz.lala
> 
> foor.bar.gigi.VALUE.baz.lala
> 
> I need to find VALUE - if this were python or something i could do it 
> but this has to be in shell -
> 
> Any clues?
Without trying to make code this early in the A.M., I'll give an
algorithm that will work entirely in shell. Then the man page should
give the details.

1. Make a subshell, either as a separate file or inline using
braces-type stuff
2. Inside that, use the set command to change the field separator to
"."
3. Use the set command with the string use wish to parse. This sets each
field into $1, $2, ...
4. Alternate algorithm # 1
   Use the shell variable $# (IIRC) to see how many you have.
   Use the shell's math capabilities to calculate the variable number
     you want
   Use the shell to generate a command (eval, backslashes, ...) to
     reference that variable
5. Alternate algorithm # 2
   do a while loop until $# = 3 (if it's already <= to 3, next is
     skipped
       shift
   access $1
6. Alternate algorithm # 3
   If $# > 3
     use shell math ability to calculate how many shifts needed
     use shift with that number as parameter
   access $1
> 
> thanks
> <snip sig stuff>
HTH
-- 
Bill