file
performs a series of tests on each file supplied by arg
and, optionally, on each file supplied in ffile
in an attempt to classify it.
If arg appears to be a text file,
file
examines the first 512 bytes
and tries to guess its programming language.
If arg is an executable
a.out,
file
prints the version stamp, provided it is greater than 0.
If arg is a symbolic link, by default the link is followed
and file tests the file that the symbolic link references.
-c
Check the magic file for format errors.
For reasons of efficiency, this validation is normally not carried out.
-fffile
ffile
contains the names
of the files to be examined.
-h
Do not follow symbolic links.
-mmfile
Use mfile as an alternate magic file,
instead of /etc/magic.
file
uses
/etc/magic
to identify files that have a magic number.
A magic number is a numeric or string constant that indicates the file type.
Commentary at the beginning of
/etc/magic
explains its format.
file classifies files containing
supplementary code set characters
according to the locale specified in the LC_CTYPE
environment variable (see LANG on
environ(5)).
file reads each argument and
can distinguish data files, program text files,
shell scripts, and executable files as follows:
Files
Classification
Data files containing supplementary characters
data
Shell scripts containing supplementary characters
command text
Language program text files containing literals
or comments using supplementary characters
xxx text
Executable files
executable
Environment variables
If POSIX2 is set, error messages are printed to standard output rather
than to standard error.
Files
/etc/magic
/usr/lib/locale/locale/LC_MESSAGES/uxcore
language-specific message file (See LANG on
environ(5).)