Using the as-yet-to-be-documented record editing capabilities of 
SolrMarc I think you can you what you want.

create a file named  in the same directory and 
SolrMarc.jar  that contains:
338_0=and(subfieldmatches("a", "online 
$aonline resource$bcr"))

and run SolrMarc as a filter:

cat   my_records.mrc  |
     java -Dsolrmarc.main.class="org.solrmarc.marc.MarcPrinter"  -jar SolrMarc.jar  translate > 

or you can even just add:

to your file, and the editing will be done as the 
records are read in for indexing.


On 6/24/2014 12:39 PM, Jonathan Rochkind wrote:
> Hi code4libbers,
> I don't have much experience with MarcEdit, I'm hoping someone else 
> does, especially with creating automated MarcEdit "tasks", and can 
> advise:
> Would it be possible to create a MarcEdit task that:
> => IF there is 338 field with subfield $a "online resource", THEN 
> erase all existing subfield $b's in that field, and add a single 
> subfield $b "cr".
> We have records loaded from certain sources that have inconsistent 
> 338$a and $b, where the $a is the reliable one. I'm curious if I can 
> send records from these sources through a MarcEdit Task to correct 
> this known pattern of error.
> Anyone know if this is possible in a MarcEdit task? And if you could 
> supply some hints to a complete newbie to MarcEdit on how to do it, 
> that would be quite kind of you!
> Jonathan