You want the conversion to be done within a script ?

Why do you want to do that ? Those things are usually done within the application.

If your intention is to just view those ZH*/JA locale characters, then you might as well change the locale information on your machine and then view those files. Instead of the machine, the locale change can be done to your xterm itself.

Very specifically, LC_ALL and LANG variables.

It would go something like this

LC_ALL=ja_JP.euc_jp
LANG=ja_JP.euc_jp

Vino