"file" command missing magic file (problem and solution)

[Andy Sun]

I encountered the following problem with command "file" in CYGWIN_NT-5.1 
v1.7.7 on a PC running Windows XP Professional.  It took me half an hour 
to figure out what the issue was so I thought I will share this and 
hopefully spare others from having to go through the same. I have done a 
quick check on the mailing list archive and could not locate similar 
reports but I have to admit that I did not look very deep as the keyword 
"file" got tons of irrelevant hits. So I apologize if this has already 
been reported.

The CYGWIN v1.7.7 distribution includes the command "file" (not part of 
the default core installation, you have to select it separately) and the 
version of "file" in this distribution is 5.04. The binary installation 
completed without any issue but when I tried to recreate the magic file 
"magic.mgc" (I need to add custom strings to it) using command "file 
-C", "file" came back with an error that it could not find any magic 
file. I rolled back one version to 5.00 and got the same error. I have 
three other machines running older distributions of CYGWIN (2004/2005) 
which have "file" versions 4.16 and 4.20, both contained the file 
/usr/share/file/magic in the binary distribution. I copied the "magic" 
file from version 4.16 to the 5.04 installation and still got the same 
error. I even downloaded the source to rebuild the binaries hoping it 
will regenerate the magic file but it didn't. I finally discovered the 
root cause after taking a closer look at the source documentation.

Apparently, somewhere between version 4.xx and 5.xx, the magic file 
which used to be /usr/share/file/magic (all my Unix life I knew magic as 
an ASCII text file), has now become a directory /usr/share/misc/magic/ 
with many small files for ease of maintenance. It also happens that this 
directory "magic" is NOT part of the binary distribution (you only get 
/usr/bin/file.exe, man page and /usr/share/misc/magic.mgc). After I 
copied the entire magic directory from the source distribution to 
/use/share/misc, "file -C" works fine and recreated magic.mgc no problem.

It would be nice if future binaries distribution of CYGWIN will include 
the directory /usr/share/misc/magic and all the files within it.

Andy

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