The Byte order mark is the Unicode character U+FEFF, and depending on the encoding it is encoded as different bytes - see "Byte order marks by encoding" on the same Wikipedia page. Because I've changed STDIN and STDOUT to be UTF-8 with the command-line switch -CS, I can use the Unicode representation and don't need to look at the bytes (although I could do that too, but I figured since everything is UTF-8 already anyway...).

$ perl -wMstrict -CSD -e 'print "\x{FEFF}"' | hexdump -C
00000000  ef bb bf                                          |...|
$ perl -wMstrict -e 'binmode STDOUT, ":raw:encoding(UTF-8)";     print
+ "\x{FEFF}"' | hexdump -C
00000000  ef bb bf                                          |...|
$ perl -wMstrict -e 'binmode STDOUT, ":raw:encoding(UTF-16-LE)"; print
+ "\x{FEFF}"' | hexdump -C
00000000  ff fe                                             |..|
$ perl -wMstrict -e 'binmode STDOUT, ":raw:encoding(UTF-16-BE)"; print
+ "\x{FEFF}"' | hexdump -C
00000000  fe ff                                             |..|
$ perl -wMstrict -e 'binmode STDOUT, ":raw:encoding(UTF-32-LE)"; print
+ "\x{FEFF}"' | hexdump -C
00000000  ff fe 00 00                                       |....|
$ perl -wMstrict -e 'binmode STDOUT, ":raw:encoding(UTF-32-BE)"; print
+ "\x{FEFF}"' | hexdump -C
00000000  00 00 fe ff                                       |....|

[download]

In reply to Re^3: perltidy and UTF-8 BOM by haukex
in thread perltidy and UTF-8 BOM by morelenmir

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.