Finding Chat Logs

Today i am searching some pdf files, ppts files in google search
I think Most of us know google search query
filetype

For Example if you want to find some material on C language
We will enter a search query like below

"c programming filetype:pdf"

It will return return all C programming pdf files..
Like that we have so many options like

filetype:doc
filetype:ppt
filetype:txt etc..

Final thing text files.. Usually log files are stored in text files..
 Can we use this option to find chat logs..? then i tried some thing like this..

something “has quit” “has joined” filetype:txt

I think you understood why i am used has quit has joined..

Oh my god surprisingly it returned so many Chat log files of unknown users..

Then i googled and found solutions for this

How this works:

Though the files found are all public,
Not everybody knows this potential logging mechanisms.

The “filetype” operator makes sure only text files are
found, and “has quit”/ “has joined” are automated messages appearing
in chat rooms.

You should replace “something” with the thing you are looking
for.

For Example

arun "has quit" "Has Joined" filetype:txt