Bash - Find files from a specific directory

I am new to bash (but not to programming). I have a bash script that looks for all .txt files in a project

for i in `find . -name "*.txt"`;
do

 basename= "${i}"
 cp ${basename} ./dest
done

However, I would like to get the .txt files only from a specific sub directory. For e.g this is my project structure:

project/
├── controllers/
│   ├── a/
│   │   ├── src/
│   │   │   ├── xxx
│   │   │   └── xxx
│   │   └── files/
│   │       ├── abc.txt
│   │       └── xxxx
│   └── b/
│       ├── src/
│       │   ├── xxx
│       │   └── xxx
│       └── files/
│           ├── abcd.txt
│           └── xxxx
├── lib
└── tests

I would like to get .txt files only from controllers/a/files and controllers/b/files. I tried replacing find . -name "*.txt" with find ./controllers/*/files/*txt, it works fine, but errors out on GitHub actions with No such file or directory found. So I'm looking for a more robust way of finding .txt files from the subdirectory without having to hardcode the path in the for loop. Is that possible?

Solution

You can use brace expansion for the search directory, e.g.

find ./project/controllers/{a,b} -type f -name "*.txt"

To select file only below ./project/controllers/a and ./project/controllers/b

Additionally, your use of basename would no longer be needed in your script (and cure the error with the ' ' (space) to the right of the '=' sign. Traditionally in bash, you will use process substitution to feed a while loop rather than using a for loop, e.g.

while read -r fname; do
  # basename="${fname}"     # note! no ' ' on either side of =
  cp -ua "$fname" ./dest
done < <(find ./project/controllers/{a,b} -type f -name "*.txt")

Edit Based On Comment of Many Paths

If you have many controllers not just a and b, then using the -path option instead of the -name options can provide a solution, e.g.

find . -path "./project/controllers/*/files/*.txt" -type f

would select any ".txt" files below any directory below controllers that contains a files directory.