Convert Ansi codepage characters to UTF-8, on the Windows command line with the free Open Source tool Swiss File Knife.

sfk atou [infile]

convert Ansi to UTF-8 text.

  -tofile x    write output to file x
  -nobom       write no BOM header
  -i           read from stdin
  -codepage=n  change codepage.
               more under: sfk listcodes

command chaining support
   accepts text or binary from a previous command.

  sfk ansitoutf    same as atou

see also
  sfk utoa       convert UTF-8 to Ansi
  sfk listcodes  list available characters
                 of your Ansi codepage

  sfk atou in.txt -tofile oututf.txt
    convert ansi to utf8 and write to file.
  sfk load in.txt +atou -tofile oututf.txt
    convert chain text.