[CentOS] grep/sed help

[Les Mikesell]

Tony Schreiner wrote:
> On Jun 10, 2009, at 2:18 PM, Joseph L. Casale wrote:
> 
>> I am rsyncing and remotely doing some work based on a logfile from
>> a windows box from a centos backup server. I get the output from a
>> vss snapshot that has a section like this:
>>
>> * SNAPSHOT ID = {639ef5df-c933-4496-878a-ed57b9d52876} ...
>>   - Shadow copy Set: {427ac5db-21be-4c53-8ca4-24e7bac86a1d}
>>   - Original count of shadow copies = 2
>>   - Original Volume name: \\?\Volume{787bdf7a- 
>> ccff-11dd-9866-806e6f6e6963}\ [D:\]
>>   - Creation Time: 6/10/2009 12:12:08 PM
>>   - Shadow copy device name: \\?\GLOBALROOT\Device 
>> \HarddiskVolumeShadowCopy11
>>   - Originating machine: milano.example.local
>>   - Service machine: milano.example.local
>>   - Not Exposed
>>   - Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
>>   - Attributes:  No_Auto_Release Persistent Differential
>>
>> * SNAPSHOT ID = {fb5996cf-a35b-4110-b83c-45f9c64a75f3} ...
>>   - Shadow copy Set: {427ac5db-21be-4c53-8ca4-24e7bac86a1d}
>>   - Original count of shadow copies = 2
>>   - Original Volume name: \\?\Volume{787bdf7b- 
>> ccff-11dd-9866-806e6f6e6963}\ [E:\]
>>   - Creation Time: 6/10/2009 12:12:08 PM
>>   - Shadow copy device name: \\?\GLOBALROOT\Device 
>> \HarddiskVolumeShadowCopy12
>>   - Originating machine: milano.example.local
>>   - Service machine: milano.example.local
>>   - Not Exposed
>>   - Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
>>   - Attributes:  No_Auto_Release Persistent Differential
>>
>> My current script only uses sed/grep but I never had to deal with  
>> this case
>> where now I need to do something based on the grep'ed/sed extraction  
>> of the
>> value of "SNAPSHOT ID" based on volume name "D:" or "E:"? To make my  
>> script
>> work without rewriting it, is there a sed method to only take the  
>> "SNAPSHOT ID"
>> if the text indented beneath it has "D:", then do the same and extract
>> "SNAPSHOT ID" if and only if "E:" follows?
>>
>> Thanks for any help!
>> jlc
> 
> 
> You could also use awk and set the record separator RS to "\n\n" and  
> the field separator to "\n". Then each record consists of 11 fields  
> consisting of each line.

Sed has a concept of 'hold' space that can be used for multiline 
matching but the syntax makes my brain hurt. I'd say the time would be 
better spent learning perl where you can use sensible programming 
techniques or a paragraph-mode regexp.

-- 
   Les Mikesell
    lesmikesell at gmail.com