Powershell 'out-file' set the encoding

out-file $file -encoding utf8

...will create what Notepad++ interprets as utf8 bom

Full set of options...

• unknown
• string
• unicode
• bigendianunicode
• utf8
• utf7
• utf32
• ascii
• default
• oem

or...

"Hello" | out-file "hello-world.txt" -encoding Unicode

What sort of files do we get?

I've run this script...

"unknown" | out-file "out-file-unknown.txt" -encoding unknown
"string" | out-file "out-file-string.txt" -encoding string
"unicode" | out-file "out-file-unicode.txt" -encoding unicode
"bigendianunicode" | out-file "out-file-bigendianunicode.txt" -encoding bigendianunicode
"utf8" | out-file "out-file-utf8.txt" -encoding utf8
"utf7" | out-file "out-file-utf7.txt" -encoding utf7
"utf32" | out-file "out-file-utf32.txt" -encoding utf32
"ascii" | out-file "out-file-ascii.txt" -encoding ascii
"default" | out-file "out-file-default.txt" -encoding default
"oem" | out-file "out-file-oem.txt" -encoding oem

And here's what notepad++ thinks of the files (note that there is significant interpretation happening for each of them... most this only tells you if a BOM is present, and if it's big or little endian)

See also

• Detect File Encoding (with Powershell)
• .net: Detect the encoding of a file
• Base64 Encode and Decode string