script.sh

#!/bin/bash

# Create or empty the output file
> results.csv

# Define the header to add at the end
header="id,balance_id,account_id,currency,amount,balance_amount,type,related_entity_type,related_entity_id,related_entity_short_reference,status,reason,settles_at,created_at,updated_at,completed_at,action,cc_account_id"

# Find all .csv files in subdirectories with "missing" in their filename
find . -type f -name "*missing*.csv" | while read -r file; do
    # Print the current file being processed
    echo "Processing file: $file"

    # Extract the directory name and get the account ID by removing the first 5 characters
    dir_name=$(dirname "$file")
    account_id=${dir_name:5}

    # Remove the first line from each file, prepend the account ID to each row, and append the result to the output file
    tail -n +2 "$file" | sed "s/^/${account_id},/" >> results.csv
    
    # Add a newline after each file's content
    echo "" >> results.csv
done

# Prepend the header to the results.csv file (using a temporary backup file for macOS compatibility)
sed -i '' "1s/^/$header\n/" results.csv

echo "Concatenation complete. Output saved to results.csv"