определить тип файла (determine file type)
Параметры (Options)
The file utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines, except
that the order of the -m, -d, and -M options shall be
significant.
The following options shall be supported by the implementation:
-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).
If the -m option is specified without specifying the -d option or
the -M option, position-sensitive default system tests shall be
applied after the position-sensitive tests specified by the -m
option. If the -M option is specified with the -d option, the -m
option, or both, or the -m option is specified with the -d
option, the concatenation of the position-sensitive tests
specified by these options shall be applied in the order
specified by the appearance of these options. If a -M or -m file
option-argument is -, the results are unspecified.
