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mime_magic('/path/to/mime.types')

    This method sets and/or returns the external magic mime types file
+ to be used for the identification of files via the mime_type method.
+ By default, MIME identification is based upon internal mime types de
+fined within the File::MMagic module.

    See File::MMagic for further details.

mime_type('field')

    This method returns the MIME type of the file uploaded through the
+ form input field named 'field' as determined by file magic numbers. 
+This is the best means by which to validate the nature of the uploade
+d file.

    See File::MMagic for further details.

File::MMagic - Guess file type

This module is to guess file type from its contents like file(1)
command.
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