file(1posix) - determine file type
-d     Apply  any  position-sensitive  default system tests and context-sensitive default system tests to
       the file. This is the default if no -M or -m option is specified.
-h     When a symbolic link is encountered, identify the file as a symbolic link. If -h is not  specified
       and  file  is a symbolic link that refers to a nonexistent file, file shall identify the file as a
       symbolic link, as if -h had been specified.
-i     If a file is a regular file, do not attempt to classify the type of the file further, but identify
       the file as specified in the STDOUT section.
-M  file
       Specify  the name of a file containing position-sensitive tests that shall be applied to a file in
       order to classify it (see the EXTENDED DESCRIPTION). No position-sensitive  default  system  tests
       nor  context-sensitive  default  system  tests  shall  be  applied  unless  the  -d option is also
       specified.
-m  file
       Specify the name of a file containing position-sensitive tests that shall be applied to a file  in
       order to classify it (see the EXTENDED DESCRIPTION).