71 lines
2.7 KiB
Plaintext
71 lines
2.7 KiB
Plaintext
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# @(#)README 1.1 98/06/16 joerg
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Find file types by using a modified "magic" file
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Based on file v3.22 by Ian F. Darwin (see libfile/LEGAL.NOTICE and
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libfile/README.dist - File v3.22 can be found at many archive sites)
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For each entry in the magic file, the "message" for the initial offset MUST
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be 4 characters for the CREATOR and 4 characters for the TYPE - white space is
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optional between them. Any other characters on this line are ignored.
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Continuation lines (starting with a '>') are also ignored i.e. only the initial
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offset lines are used.
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e.g magic entry for a GIF file:
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# off type test message
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#
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# GIF image
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0 string GIF8 8BIM GIFf
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>4 string 7a \b, version 8%s,
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>4 string 9a \b, version 8%s,
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>6 leshort >0 %hd x
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>8 leshort >0 %hd,
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#>10 byte &0x80 color mapped,
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#>10 byte&0x07 =0x00 2 colors
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#>10 byte&0x07 =0x01 4 colors
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#>10 byte&0x07 =0x02 8 colors
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#>10 byte&0x07 =0x03 16 colors
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#>10 byte&0x07 =0x04 32 colors
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#>10 byte&0x07 =0x05 64 colors
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#>10 byte&0x07 =0x06 128 colors
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#>10 byte&0x07 =0x07 256 colors
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Just the "8BIM" "GIFf" will be used whatever the type of GIF file it is.
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The continuation lines are used by the "file" command, but ignored by
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mkhybrid. They could be left out completely.
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The complete format of the magic file is given in the magic man page (magic.5).
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See the file "magic" for other examples
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Use with the -magic magic_file option, where magic_file is a file
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described above.
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The magic file can be used with the mapping file (option -map) - the order
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these options appear on the command line is important. mkhybrid will try to
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detect if the file is one of the Unix/Mac files (e.g. a CAP or Netatalk
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file) first. If that fails, it will then use the magic and/or mapping
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file e.g:
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mkhybrid -o output.raw -map mapping -magic magic src_dir
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The above will check filename extensions first, if that fails to set the
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CREATOR/TYPE, the magic file will be used. To check the magic file
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before the filename extensions, use:
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mkhybrid -o output.raw -magic magic -map mapping src_dir
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Using just a magic file - filename extensions will not be checked e.g:
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mkhybrid -o output.raw -magic magic src_dir
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For the magic method to work, each file must be opened and read twice
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(once to find it's CREATOR/TYPE, and a second time to actually copy the
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file to the CD image). Therefore the -magic option may significantly
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increase processing time.
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If a file's CREATOR/TYPE is not set via the magic and mapping matches,
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then the file is given the default CREATOR/TYPE.
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