$ echo a;b > example.csv
$ echo d;e >> example.csv
$ hexdump -C example.csv
00000000  61 3b 62 0a 64 3b 65 0a                           |a;b.d;e.|
00000008
$ uconv --add-signature example.csv | hexdump -C
00000000  ef bb bf 61 3b 62 0a 64  3b 65 0a                 |...a;b.d;e.|
0000000b