compare files in two folders

folders_files_comparishon.sh

#!/bin/bash

# Argument passing and checking
while getopts 't:r:' flag; do
    case "${flag}" in
    t) TARGETDIR="${OPTARG}" ;;
    r) REFDIR="${OPTARG}" ;;
    *)
        echo "usage: $0 [-t] [-r]" >&2
        exit 1
        ;;
    esac
done

if [ -z "$TARGETDIR" ] || [ -z "$REFDIR" ]; then
    echo "Missing required paths"
    exit 1
fi

ref_list=()
for f in $(find "$REFDIR" -type f); do
    base_name=$(basename "$f")
    ref_list+=("$base_name")
done

target_list=()
for f in $(find "$TARGETDIR" -type f); do
    base_name=$(basename "$f")
    target_list+=("$base_name")
done

# sort lists
sorted_ref=$(echo "${ref_list[@]}" | tr ' ' '\n' | sort | uniq)
sorted_target=$(echo "${target_list[@]}" | tr ' ' '\n' | sort | uniq)

# actual test
echo -e "\nprinting files from $REFDIR missing  in $TARGETDIR\n"
unique_to_list1=$(comm -23 <(echo "${sorted_ref[@]}") <(echo "${sorted_target[@]}"))
echo "$unique_to_list1"

echo -e "\n(if nothing was printed, then all files from $REFDIR are present in $TARGETDIR)"