For each file given in its command line, mimeview attempts to autodetect its type and invoke an appropriate file viewer.
To detect the file type, mimeview uses mime.types file. This file is a part of Common UNIX Printing System, mime.types. By default mimeview searches for mime.types in $prefix/etc/cups/1, however its exact location can be specified at runtime as well (see --mimetypes below).
Once file MIME type is successfully determined, mimeview
consults mailcap files in order to determine how to display
the file. It does so essentially in the same manner as
metamail utility, i.e., it scans all files specified
in METAMAIL environment variable until it finds an entry
describing the desired file format or until the list of files is
exhausted. If METAMAIL variable is not set, mimeview
uses the following default path instead:
$HOME/.mailcap:/usr/local/etc/mailcap:\
/usr/etc/mailcap:/etc/mailcap:\
/etc/mail/mailcap:/usr/public/lib/mailcap
[1] The exact location is determined at configuration time by setting environment variable DEFAULT_CUPS_CONFDIR. On most sites running
./configure DEFAULT_CUPS_CONFDIR=/etc/cups
should be recommended.