GREP Style Inquiry: Adding a period to an abbreviation that doesn't already have one?

[ACI_Design]

Hey there, 

I'm currently in the throws of creating an in-depth directory for the US Forest Service- which has resulted in my having to utilize GREP Styles- which has been fabulously effective. 

The only thing I was given was a very poorly executed (disorganized, poor punctuation, that kind of thing) spreadsheet. So, yea- Scripts and GREP have really saved me here. 

Anyway, I have stumbled across something I'm sure will prove to be very simple to all you Adobe Wizards; I'm hoping I may tap into your wisdom.

I need to add a period to the abbreviation "Ext" so that it reads "Ext."

I've only been successful so far in adding a period to all instances of "Ext", even if that already have a period- which results in many of the instances reading "Ext.." - How do I avoid that? 

Thank you in advance,

 - Vitto

[kglad]

is this an acrobat question?

[ACI_Design]

Woops, I apologize! The program is InDesign.

[kglad]

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post if it helps you get responses.

<"moved from using the community">

[ACI_Design]

Oh, my bad lol.

I'll go ahead and re-post to the InDesign Support Community! Totally thought I did that to begin with, thank you for pointing me in the right direction!!

[kglad]

no need. i moved your post.

[Scott Falkner]

Ext(?!\.)

Use the above search. It looks for Ext without a period immediately following it. You can see the only instance it found below.