Butler trigger id
Asked by G?ran Langga?rd:

hi there! I?m stuck on finding the logic for a basic butler trigger id..

I try to populate a custom field, from a custom field combined with the value from a prefix in said custom field.

this rule works perfect:

when a card is added to the board, set custom field "NC Task id" to {triggercardnumber}"

BUT, I have in the power up "card numbers" set a prefix to each of our boards to be able to give them a unique id across boards. I am not able to pick up this prefix trigger from butler? as I would like it to popular the field with prefix then cardnumber.

![cardnumberprefix.png](/t5/image/serverpage/image-id/66877iD4D35A066EF302F9/image-size/large?v=v2&px=999 "cardnumberprefix.png")

basically I can make the rule to add a prefix by just typing it in the rule, but that would force me to create a separate rule for each new board..

anyone able to help me?


Answers:
author: Katrin Anger
body: [@G?ran Langga?rd](/t5/user/viewprofilepage/user-id/3566095)

I think that's bad luck.

You are using a 3rd party add-on. Whilst these add-ons usually work fine, they rarely work well with each other.

comments: author: G?ran Langga?rd
body: cheers, yeah I guess that's bad luck.. but irony is that it works well on the first half of the logic (from the same 3rd party add-on).. I was most curious if someone had managed to single out the variable name for the prefix..

\*and pS if you could help me with the variable for how to make butler populate and empty cell (i.e I have a huge number of cards with a blank custom field, I need that field filled out with a value. everything works except Butler cannot (in my hands at least) recognise an empty cell until its content is i.e deleted then I can make the logic work..


author: Katrin Anger
body: [@G?ran Langga?rd](/t5/user/viewprofilepage/user-id/3566095)

I am not sure if I get you right. But populating a blank custom field or clearing a custom field is quite easy with Butler.

I have recently published an [article](https://medium.com/workflow-automation-with-trello/making-a-difference-with-custom-field-workflows-in-trello-c294c2b792d7) with 5 hacks for custom fields in Trello. Hack #2 explains how to populate a custom field by default.

Are you using the action "set custom field XXX to YYY", and are you saying that Butler isn't overwriting an already existing value with "YYY"?

If so, I'd contact the Trello support. You might have come across a bug.

-- Does that help?


author: G?ran Langga?rd
body: thx for your reply!

the hacks where a good read for sure, figured most of that out the hard ways though;-)

I see I was bad at explaining.. I?m sure what I want is so basic there got to be a solution to it.. I?ve just run myself blind..

I just need to create a rule that identifies and populates blank custom field x with value y (see below for illustration..)

![custom field empty.png](https://community.atlassian.com/t5/image/serverpage/image-id/66905iA271C0B99AA03D68/image-size/large?v=v2&px=999 "custom field empty.png")


author: Katrin Anger
body: [@G?ran Langga?rd](/t5/user/viewprofilepage/user-id/3566095)

Okay, I now understand what you mean. There isn't an option currently, that would target only blank custom fields.

The only thing you could do is setting up a feature request and requesting this. They do keep working on Butler, so this might be responded to.

If you want to do this, click on 3 dots in the upper Butler right screen, and then on Feedback \& Feature Requests.


author: Iain Dooley
body: [@G?ran Langga?rd](/t5/user/viewprofilepage/user-id/3566095) this Trellinator command will set all the blank custom fields to a given value:

<https://gist.github.com/iaindooley/c1ce15aa4a093936afbfbe42d316f5b7>

You can read more about Trellinator here:

<https://community.atlassian.com/t5/Marketplace-Apps-Integrations/Introducing-Trellinator-Automate-Trello-with-Google-Apps-Script/ba-p/925271>


Tags: butler

trigger