Convert txt file from UTF to other codepage - command line

Anyone hear about a commandline utility to convert txt files between codepages?
I need something to convert file from Win1250 to UTF (and back). Good, if this tool can detect what format already if used.

Plz help :frowning:

Try gżegżółka

Not working - as i say, this program must working in command line (to create button in dopus)

Gżegółka has a command line interface.

Yes, my mistake