파일내 특정 한글 문자가 있는지 알아내는 프로그램을 만들고 싶어요

#!/bin/bash
 
function guess-encoding() {
    supported=()
    input=$1
    shift
    for enc in "$@"; do
        iconv -f "$enc" -t utf-8 "$input" >/dev/null 2>&1
        if [[ $? == 0 ]]; then
            supported+=("$enc");
        fi
    done
    echo ${supported[@]}
    return 0;
}
 
 
for file in "$@"; do
    failed=0
    for enc in `guess-encoding "$file" cp949 utf-8`; do
        iconv -t ASCII -f "$enc" "$file" >/dev/null 2>&1
        if [[ $? -ne 0 ]]; then
            failed=1
            echo "$file: may have non-ASCII text"
            break;
        fi
    done
 
    if [[ $failed == 0 ]]; then
        echo "$file: contains ASCII only"
    fi
done

$ ./has-hangul.sh hangul.txt english.txt
hangul.txt: may have non-ASCII text
english.txt: contains ASCII only