How to pass file names as variables to an executable program?

Question

This should be a relatively simple question. I am trying to pass multiple files through an executable program in a loop. I have tried multiple strategies (storing in an array, etc.) but the file name does not seem to be recognized as a variable. The error I am getting is: No such file or directory.

The outline of my latest attempt:

FILES=path/*/*

for f in $FILES
do
./function -input $f 
done

I am working in a bash shell.

Answer 1

Instead of using a plain variable to store a glob expansion sequence, recommend using a proper array and enable shell globbing option globstar to populate files in all sub-directories

shopt -s globstar nullglob
file_list=(path/**/*)

and use a loop over the array to process on each file

for file in "${file_list[@]}"; do
    printf '%s\n' "$file"
    # Your other actions on file goes here
done