How to assign a string value from a subsearch to a eval which should map to all the events?

[sudeshna_dash]

I am trying to extract a value and add it to every events of that sourcetype.

source="c:\\splunk monitors\\log(2).txt"  | eval ServiceTag = [search source="c:\\splunk monitors\\log(2).txt" | head 1 |  rex field=_raw "^[^\[\n]*\[(?P<SvcTag>[^\]]+)" | eval tag = SvcTag | return $tag ]

Here $tag returns 5Q4RZH2 which is a string and thus, it is not able to get stored in ServiceTag variable of eval.
If the tag would have returned some number such as "123" then it is able to store the same.
E.g.

    source="c:\\splunk monitors\\log(2).txt"  | eval ServiceTag = [search source="c:\\splunk monitors\\log(2).txt" | head 1 |  rex field=_raw "^[^\[\n]*\[(?P<SvcTag>[^\]]+)" | eval tag = "123"| return $tag ]

In this scenario, ServiceTag has the value 123
Hence, it is getting difficult to store a string.

Can someone please solve?

[niketn]

@sudeshna_dash, are you doing it in a dashboard? Can you add some sample data and post the example above using code button?

[HiroshiSatoh · Accepted solution]

Try this!

| eval tag = SvcTag | return $tag ]
↓
| eval tag = "\""+SvcTag+"\"" | return $tag ]

[sudeshna_dash]

Thanks a lot @HiroshiSatoh, this worked. I am grateful to u

[mayurr98]

Try

source="c:\\splunk monitors\\log(2).txt"  | eval ServiceTag =case( [search source="c:\\splunk monitors\\log(2).txt" | head 1 |  rex field=_raw "^[^\[\n]*\[(?P<SvcTag>[^\]]+)" | eval tag = SvcTag | return 10000 tag ],tag)

Let me know if this helps!

[sudeshna_dash]

Thanks @mayurr98 but this doesn't solve the problem