iconv

Check all by content in test.txt

for i in $(iconv -l | tr ',' '\n' | tr -d '//'); do s=$(iconv -f $i -t UTF8 test.txt 2>/dev/null); echo "$i:  $s"; done > result.txt

Cyrillic

echo "Çàïèñê" | iconv -t latin1 | iconv -f cp1251