linux - how to detect invalid utf8 unicode/binary in a text file

I need to detect corrupted text file where there are invalid (non-ASCII) utf-8, Unicode or binary characters.

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what I have tried:

iconv -f utf-8 -t utf-8 -c file.csv 

this converts a file from utf-8 encoding to utf-8 encoding and -c is for skipping invalid utf-8 characters. However at the end those illegal characters still got printed. Are there any other solutions in bash on linux or other languages?