$ cat foo.fsx
printf "äöü\n"
$ LANG='en_US.UTF-8' fsharpi foo.fsx | hd
00000000  c3 a4 c3 b6 c3 bc 0a                              |.......|
00000007
$ LANG='en_DK.UTF-8' fsharpi foo.fsx | hd
00000000  c3 a4 c3 b6 c3 bc 0a                              |.......|
00000007
$ LANG='en_DK.ISO-8859-15' fsharpi foo.fsx | hd
00000000  c3 a4 c3 b6 c3 bc 0a                              |.......|
00000007
$ LANG='en_DK.GARBAGE' fsharpi foo.fsx | hd
00000000  3f 3f 3f 0a                                       |???.|
00000004