How can I check if a utf-8 text file have a BOM from command line?

file command shows me UTF-8 Unicode text.

But I don't know it means there is no BOM in the file.

I'm using Ubuntu 12.04.

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  • Note that there is no BOM in UTF-8: that's a feature of UTF-16. An UTF-8 file may start with the U+FEFF character, but in that case it's a zero-width space. – Gilles 'SO- stop being evil' Dec 2 '14 at 14:16

file will tell you if there is a BOM. You can test:

$ /usr/bin/printf "\ufeff...\n" | file -
/dev/stdin: UTF-8 Unicode (with BOM) text

Note: according to the file changelog, this feature existed already in 2007. So, this should work on any current machine.

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  • 1
    Thanks for answer. My file version is file-5.09 and the result was /dev/stdin: ASCII text. Is it depends on version of file? – ironsand Dec 1 '14 at 3:55
  • @Tetsu I tested with file 5.04 (Debian squeeze) and it was OK. Even in 2007, according to the changelog (not tested). But you can do the test I've given in my answer. – vinc17 Dec 1 '14 at 3:57
  • I just installed language-pack-ja from apt, then your example works perfectly. Thanks for your help! – ironsand Dec 1 '14 at 4:18

If you execute stat fileName it should give you exact the three characters. When I opened the file in the editor, I was unable to see anything. So noticing that the file size was 3 gave me clarity that it has a BOM.

Also, the post here was helful in my case.

hexdump -n 3 -C 2.txt
00000000 ef bb bf
ef bb bf // YES
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