1
# @(#)README 1.1 98/06/16 joerg
3
Find file types by using a modified "magic" file
5
Based on file v3.22 by Ian F. Darwin (see libfile/LEGAL.NOTICE and
6
libfile/README.dist - File v3.22 can be found at many archive sites)
8
For each entry in the magic file, the "message" for the initial offset MUST
9
be 4 characters for the CREATOR and 4 characters for the TYPE - white space is
10
optional between them. Any other characters on this line are ignored.
11
Continuation lines (starting with a '>') are also ignored i.e. only the initial
12
offset lines are used.
14
e.g magic entry for a GIF file:
16
# off type test message
19
0 string GIF8 8BIM GIFf
20
>4 string 7a \b, version 8%s,
21
>4 string 9a \b, version 8%s,
24
#>10 byte &0x80 color mapped,
25
#>10 byte&0x07 =0x00 2 colors
26
#>10 byte&0x07 =0x01 4 colors
27
#>10 byte&0x07 =0x02 8 colors
28
#>10 byte&0x07 =0x03 16 colors
29
#>10 byte&0x07 =0x04 32 colors
30
#>10 byte&0x07 =0x05 64 colors
31
#>10 byte&0x07 =0x06 128 colors
32
#>10 byte&0x07 =0x07 256 colors
34
Just the "8BIM" "GIFf" will be used whatever the type of GIF file it is.
35
The continuation lines are used by the "file" command, but ignored by
36
mkhybrid. They could be left out completely.
38
The complete format of the magic file is given in the magic man page (magic.5).
40
See the file "magic" for other examples
42
Use with the -magic magic_file option, where magic_file is a file
45
The magic file can be used with the mapping file (option -map) - the order
46
these options appear on the command line is important. mkhybrid will try to
47
detect if the file is one of the Unix/Mac files (e.g. a CAP or Netatalk
48
file) first. If that fails, it will then use the magic and/or mapping
51
mkhybrid -o output.raw -map mapping -magic magic src_dir
53
The above will check filename extensions first, if that fails to set the
54
CREATOR/TYPE, the magic file will be used. To check the magic file
55
before the filename extensions, use:
57
mkhybrid -o output.raw -magic magic -map mapping src_dir
60
Using just a magic file - filename extensions will not be checked e.g:
62
mkhybrid -o output.raw -magic magic src_dir
64
For the magic method to work, each file must be opened and read twice
65
(once to find it's CREATOR/TYPE, and a second time to actually copy the
66
file to the CD image). Therefore the -magic option may significantly
67
increase processing time.
69
If a file's CREATOR/TYPE is not set via the magic and mapping matches,
70
then the file is given the default CREATOR/TYPE.