Loop round folders to find and list which folders contain a file excluding a keyword, in bash?

Question

I want to loop through thousands of folders all which contain a file called output(foldernumber).txt and check which of these output files DO NOT contain a keyword and have the script write out a list of these output files, so further analysis can be completed on them.

This is what I have so far:

a=1
b=1
for i in ~pwd ;do
(cd $i/ && grep -L 'keyword' output"$a".txt >> ../list.txt)
a=$((a+b))
done

Errors given say the output files do not exist and a blank list.txt file is made. Any advice please?

Answer 1

find . -type f -regex ".*/output[0-9]*\.txt" -exec grep -L 'keyword' '{}' +

or

 find . -type f -regex ".*/output[0-9]*\.txt" -print0 | xargs -0 grep -L 'keyword'