I have found a little bug (i guess). See that:

a=danilo

echo $a | cut -c -5 # shows danil

a=dánilo

echo $a | cut -c 5 # shows dáni

The option -b equal works. The cut is ignoring the letters with acentuation.

I read in infopages this: 

`-c CHARACTER-LIST'

`--characters=CHARACTER-LIST'

     Select for printing only the characters in positions listed in

     CHARACTER-LIST.  The same as `-b' for now, but

     internationalization will change that.  Tabs and backspaces are

     treated like any other character; they take up 1 character.  If an

     output delimiter is specified, (see the description of

     `--output-delimiter'), then output that string between ranges of

     selected bytes.

"The same as `-b' for now, but

     internationalization will change that." this solves my problem? How it works?

Thanks,

Danilo S. Morăes