file(1) General Commands Manual file(1)
NAME
file - determine file type
SYNOPSIS
mfile] ffile] file ...
UNIX 2003 (onwards) Synopsis
mfile] Mfile] ffile] file ...
DESCRIPTION
performs a series of tests on each file in an attempt to classify it. If file appears to be an ASCII file, examines the first 512 bytes
and tries to guess its language. If file is an executable file, prints the version stamp, provided it is greater than 0 (see the descrip-
tion of the option in ld(1)).
uses the file to identify files that have some sort of that is, any file containing a numeric or string constant that indicates its type.
Commentary at the beginning of explains the format.
Options
recognizes the following command-line options:
Use alternate magic file
mfile.
(UNIX 2003 onwards Only)
Use alternate magic file Mfile. Do not apply default context-sensitive tests.
Check the magic file for format errors.
This validation is not normally carried out for reasons of efficiency. No file classification is done when this option
is specified.
(UNIX 2003 onwards Only)
Apply position-sensitive tests from the default magic file, and default context-sensitive tests to the file.
Obtain the list of files to be examined from file
ffile. classifies each file whose name appears in ffile.
Do not follow symbolic links.
From UNIX 2003 (onwards) environment, if is not specified and the is a symbolic link referring to a non-existent file, it
is identified as a symbolic link, as if has been specified.
Do not attempt to classify a regular file further.
If the option is specified with the option, option, or both, the concatenation of the position-sensitive tests specified by these
options is applied in the order specified by the appearance of these options.
EXTERNAL INFLUENCES
For information about the UNIX standard environment, see standards(5).
Environment Variables
determines the language in which messages are displayed.
If is not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty vari-
able. If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of
If any internationalization variable contains an invalid setting, behaves as if all internationalization variables are set to "C". See
environ(5).
International Code Set Support
Single- and multi-byte character code sets are supported. However, all non-ASCII text files are identified as "data".
WARNINGS
The command for a release interprets the core files for that particular release correctly. Using the command on a core file generated on a
different release will report incorrect results.
SEE ALSO
ld(1), standards(5).
STANDARDS CONFORMANCE
file(1)
Check Out this Related Man Page
file(1) User Commands file(1)
NAME
file - determine file type
SYNOPSIS
/usr/bin/file [-dh] [-m mfile] [-M Mfile] [-f ffile] file...
/usr/bin/file [-dh] [-m mfile] [-M Mfile] -f ffile
/usr/bin/file -i [-h] [-f ffile] file...
/usr/bin/file -i [-h] -f ffile
/usr/bin/file -c [-d] [-m mfile] [-M Mfile]
/usr/xpg4/bin/file [-dh] [-m mfile] [-M Mfile] [-f ffile] file...
/usr/xpg4/bin/file [-dh] [-m mfile] [-M Mfile] -f ffile
/usr/xpg4/bin/file -i [-h] [-f ffile] file...
/usr/xpg4/bin/file -i [-h] -f ffile
/usr/xpg4/bin/file -c [-d] [-m mfile] [-M Mfile]
DESCRIPTION
The file utility performs a series of tests on each file supplied by file and, optionally, on each file listed in ffile in an attempt to
classify it. If the file is not a regular file, its file type is identified. The file types directory, FIFO, block special, and character
special are identified as such. If the file is a regular file and the file is zero-length, it is identified as an empty file.
If file appears to be a text file, file examines the first 512 bytes and tries to determine its programming language. If file is a symbolic
link, by default the link is followed and file tests the file to which the symbolic link refers.
If file is a relocatable object, executable, or shared object, file prints out information regarding the file's execution requirements.
This information includes the machine class, byte-ordering, static or dynamic linkage, and any software or hardware capability require-
ments.
By default, file will try to use the localized magic file /usr/lib/locale/locale/LC_MESSAGES/magic, if it exists, to identify files that
have a magic number. For example, in the Japanese locale, file will try to use /usr/lib/locale/ja/LC_MESSAGES/magic. If a localized magic
file does not exist, file will utilize /etc/magic. A magic number is a numeric or string constant that indicates the file type. See
magic(4) for an explanation of the format of /etc/magic.
If file does not exist, cannot be read, or its file status could not be determined, it is not considered an error that affects the exit
status. The output will indicate that the file was processed, but that its type could not be determined.
OPTIONS
The following options are supported:
-c Checks the magic file for format errors. For reasons of efficiency, this validation is normally not carried out.
-d Applies any position-sensitive and context-sensitive default system tests to the file.
-f ffile ffile contains a list of the files to be examined.
-h When a symbolic link is encountered, this option identifies the file as a symbolic link. If -h is not specified and file is
a symbolic link that refers to a non-existent file, the file utility identifies the file as a symbolic link, as if -h had
been specified.
-i If a file is a regular file, this option does not attempt to classify the type of file further, but identifies the file as
a "regular file".
-m mfile
/usr/bin/file
Uses mfile as an alternate magic file, instead of /etc/magic.
/usr/xpg4/bin/file
Specifies the name of a file containing position-sensitive tests that are applied to a file in order to classify it
(see magic(4)). If the -m option is specified without specifying the -d option or the -M option, position-sensitive
default system tests are applied after the position-sensitive tests specified by the -m option.
-M Mfile Specifies the name of a file containing position-sensitive tests that are applied to a file in order to classify it (see
magic(4)). No position-sensitive default system tests nor context-sensitive default system tests are applied unless the -d
option is also specified.
If the -M option is specified with the -d option, the -m option, or both, or if the -m option is specified with the -d option, the concate-
nation of the position-sensitive tests specified by these options is applied in the order specified by the appearance of these options.
OPERANDS
The following operands are supported:
file A path name of a file to be tested.
USAGE
See largefile(5) for the description of the behavior of file when encountering files greater than or equal to 2 Gbyte ( 2**31 bytes).
EXAMPLES
Example 1: Binary executable files
Determine if an argument is a binary executable file:
file "$1" | grep -Fq executable &&
printf "%s is executable.
" "$1"
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of file: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
FILES
/etc/magic file's magic number file
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|CSI |enabled |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO
elfdump(1), ls(1), magic(4), attributes(5), environ(5), largefile(5), standards(5)
SunOS 5.10 16 July 2004 file(1)