topic Re: Use named backreference in the subsequent rex command in Splunk Search

Use named backreference in the subsequent rex command

Murali2888 — Wed, 12 Aug 2015 12:00:06 GMT

Hi All,

Can you let me know how we can use a named backreference in the subsequent rex command? That is pass the value of the named backreference to the next rex command.

I am trying something like below which is not providing the desired result.

rex "<tag1>(?P<NamedField1>[^<]+" | rex "<tag2>?(P=NamedField1)</tag2><tag3>(?P<NamedField2>)" | table NamedField2

If someone could point out some documentation around this that would be very helpful.

Re: Use named backreference in the subsequent rex command

maciep — Thu, 13 Aug 2015 01:53:00 GMT

Not exactly what you're asking, but you can use \n to represent a previously captured group in the same rex command. So in your case, something like

rex "<tag1>(?P<NamedField1>[^<]+").+<tag2>\1</tag2><tag3>(?P<NamedField2>)"

Although I'm pretty sure i found a way to substitute field names in the rex too, but don't remember and could be mistaken.

Re: Use named backreference in the subsequent rex command

Murali2888 — Fri, 28 Aug 2015 05:13:23 GMT

Thanks maciep.

I had this option, but unfortunately the xml structure is quite redundant and complex which would not allow using a single rex command. Nevertheless, I had found some workaround with eval command.