Iterate through a bash file and do some things

bash_file_iterate.sh

for i in raw/*.json; 
  do 

    # Create new filename

    filename=$(basename -- "$i")
    extension="${filename##*.}"
    filename="${filename%.*}"
    new_filename=processed/refs_${filename}.txt

    # Shuffle the first 1000 rows, and extract the reference sections
    # then save as a new file.

    cat $i | shuf | head -n 1000 | jq .sections.Reference > ${new_filename}
    
    # Remove all the null values created by jq
    
    sed /^null$/d -i ${new_filename}
    echo "Output ${new_filename}"
  done