DragonFly On-Line Manual Pages
FILE(1) DragonFly General Commands Manual FILE(1)
NAME
file - determine file type
SYNOPSIS
file [-bcdEhiklLNnprsSvzZ0] [--apple] [--exclude-quiet] [--extension]
[--mime-encoding] [--mime-type] [-e testname] [-F separator]
[-f namefile] [-m magicfiles] [-P name=value] file ...
file -C [-m magicfiles]
file [--help]
DESCRIPTION
This manual page documents version 5.40 of the file command.
file tests each argument in an attempt to classify it. There are three
sets of tests, performed in this order: filesystem tests, magic tests,
and language tests. The first test that succeeds causes the file type to
be printed.
The type printed will usually contain one of the words text (the file
contains only printing characters and a few common control characters and
is probably safe to read on an ASCII terminal), executable (the file
contains the result of compiling a program in a form understandable to
some UNIX kernel or another), or data meaning anything else (data is
usually "binary" or non-printable). Exceptions are well-known file
formats (core files, tar archives) that are known to contain binary data.
When modifying magic files or the program itself, make sure to preserve
these keywords. Users depend on knowing that all the readable files in a
directory have the word "text" printed. Don't do as Berkeley did and
change "shell commands text" to "shell script".
The filesystem tests are based on examining the return from a stat(2)
system call. The program checks to see if the file is empty, or if it's
some sort of special file. Any known file types appropriate to the
system you are running on (sockets, symbolic links, or named pipes
(FIFOs) on those systems that implement them) are intuited if they are
defined in the system header file <sys/stat.h>.
The magic tests are used to check for files with data in particular fixed
formats. The canonical example of this is a binary executable (compiled
program) a.out file, whose format is defined in <elf.h>, <a.out.h> and
possibly <exec.h> in the standard include directory. These files have a
"magic number" stored in a particular place near the beginning of the
file that tells the UNIX operating system that the file is a binary
executable, and which of several types thereof. The concept of a "magic
number" has been applied by extension to data files. Any file with some
invariant identifier at a small fixed offset into the file can usually be
described in this way. The information identifying these files is read
from the compiled magic file /usr/share/misc/magic.mgc, or the files in
the directory /usr/share/misc/magic if the compiled file does not exist.
In addition, if $HOME/.magic.mgc or $HOME/.magic exists, it will be used
in preference to the system magic files.
If a file does not match any of the entries in the magic file, it is
examined to see if it seems to be a text file. ASCII, ISO-8859-x, non-
ISO 8-bit extended-ASCII character sets (such as those used on Macintosh
and IBM PC systems), UTF-8-encoded Unicode, UTF-16-encoded Unicode, and
EBCDIC character sets can be distinguished by the different ranges and
sequences of bytes that constitute printable text in each set. If a file
passes any of these tests, its character set is reported. ASCII,
ISO-8859-x, UTF-8, and extended-ASCII files are identified as "text"
because they will be mostly readable on nearly any terminal; UTF-16 and
EBCDIC are only "character data" because, while they contain text, it is
text that will require translation before it can be read. In addition,
file will attempt to determine other characteristics of text-type files.
If the lines of a file are terminated by CR, CRLF, or NEL, instead of the
Unix-standard LF, this will be reported. Files that contain embedded
escape sequences or overstriking will also be identified.
Once file has determined the character set used in a text-type file, it
will attempt to determine in what language the file is written. The
language tests look for particular strings (cf. <names.h>) that can
appear anywhere in the first few blocks of a file. For example, the
keyword .br indicates that the file is most likely a troff(1) input file,
just as the keyword struct indicates a C program. These tests are less
reliable than the previous two groups, so they are performed last. The
language test routines also test for some miscellany (such as tar(1)
archives, JSON files).
Any file that cannot be identified as having been written in any of the
character sets listed above is simply said to be "data".
OPTIONS
--apple
Causes the file command to output the file type and creator code
as used by older MacOS versions. The code consists of eight
letters, the first describing the file type, the latter the
creator. This option works properly only for file formats that
have the apple-style output defined.
-b, --brief
Do not prepend filenames to output lines (brief mode).
-C, --compile
Write a magic.mgc output file that contains a pre-parsed version
of the magic file or directory.
-c, --checking-printout
Cause a checking printout of the parsed form of the magic file.
This is usually used in conjunction with the -m option to debug a
new magic file before installing it.
-d Prints internal debugging information to stderr.
-E On filesystem errors (file not found etc), instead of handling
the error as regular output as POSIX mandates and keep going,
issue an error message and exit.
-e, --exclude testname
Exclude the test named in testname from the list of tests made to
determine the file type. Valid test names are:
apptype EMX application type (only on EMX).
ascii Various types of text files (this test will try to
guess the text encoding, irrespective of the setting of
the `encoding' option).
encoding Different text encodings for soft magic tests.
tokens Ignored for backwards compatibility.
cdf Prints details of Compound Document Files.
compress Checks for, and looks inside, compressed files.
csv Checks Comma Separated Value files.
elf Prints ELF file details, provided soft magic tests are
enabled and the elf magic is found.
json Examines JSON (RFC-7159) files by parsing them for
compliance.
soft Consults magic files.
tar Examines tar files by verifying the checksum of the 512
byte tar header. Excluding this test can provide more
detailed content description by using the soft magic
method.
text A synonym for `ascii'.
--exclude-quiet
Like --exclude but ignore tests that file does not know about.
This is intended for compatibility with older versions of file.
--extension
Print a slash-separated list of valid extensions for the file
type found.
-F, --separator separator
Use the specified string as the separator between the filename
and the file result returned. Defaults to `:'.
-f, --files-from namefile
Read the names of the files to be examined from namefile (one per
line) before the argument list. Either namefile or at least one
filename argument must be present; to test the standard input,
use `-' as a filename argument. Please note that namefile is
unwrapped and the enclosed filenames are processed when this
option is encountered and before any further options processing
is done. This allows one to process multiple lists of files with
different command line arguments on the same file invocation.
Thus if you want to set the delimiter, you need to do it before
you specify the list of files, like: "-F @ -f namefile", instead
of: "-f namefile -F @".
-h, --no-dereference
This option causes symlinks not to be followed (on systems that
support symbolic links). This is the default if the environment
variable POSIXLY_CORRECT is not defined.
-i, --mime
Causes the file command to output mime type strings rather than
the more traditional human readable ones. Thus it may say
`text/plain; charset=us-ascii' rather than "ASCII text".
--mime-type, --mime-encoding
Like -i, but print only the specified element(s).
-k, --keep-going
Don't stop at the first match, keep going. Subsequent matches
will be have the string `\012- ' prepended. (If you want a
newline, see the -r option.) The magic pattern with the highest
strength (see the -l option) comes first.
-l, --list
Shows a list of patterns and their strength sorted descending by
magic(5) strength which is used for the matching (see also the -k
option).
-L, --dereference
This option causes symlinks to be followed, as the like-named
option in ls(1) (on systems that support symbolic links). This
is the default if the environment variable POSIXLY_CORRECT is
defined.
-m, --magic-file magicfiles
Specify an alternate list of files and directories containing
magic. This can be a single item, or a colon-separated list. If
a compiled magic file is found alongside a file or directory, it
will be used instead.
-N, --no-pad
Don't pad filenames so that they align in the output.
-n, --no-buffer
Force stdout to be flushed after checking each file. This is
only useful if checking a list of files. It is intended to be
used by programs that want filetype output from a pipe.
-p, --preserve-date
On systems that support utime(3) or utimes(2), attempt to
preserve the access time of files analyzed, to pretend that file
never read them.
-P, --parameter name=value
Set various parameter limits.
Name Default Explanation
bytes 1048576 max number of bytes to read from
file
elf_notes 256 max ELF notes processed
elf_phnum 2048 max ELF program sections processed
elf_shnum 32768 max ELF sections processed
encoding 65536 max number of bytes to scan for
encoding evaluation
indir 50 recursion limit for indirect magic
name 50 use count limit for name/use magic
regex 8192 length limit for regex searches
-r, --raw
Don't translate unprintable characters to \ooo. Normally file
translates unprintable characters to their octal representation.
-s, --special-files
Normally, file only attempts to read and determine the type of
argument files which stat(2) reports are ordinary files. This
prevents problems, because reading special files may have
peculiar consequences. Specifying the -s option causes file to
also read argument files which are block or character special
files. This is useful for determining the filesystem types of
the data in raw disk partitions, which are block special files.
This option also causes file to disregard the file size as
reported by stat(2) since on some systems it reports a zero size
for raw disk partitions.
-S, --no-sandbox
On systems where libseccomp
(https://github.com/seccomp/libseccomp) is available, the -S
option disables sandboxing which is enabled by default. This
option is needed for file to execute external decompressing
programs, i.e. when the -z option is specified and the built-in
decompressors are not available. On systems where sandboxing is
not available, this option has no effect.
-v, --version
Print the version of the program and exit.
-z, --uncompress
Try to look inside compressed files.
-Z, --uncompress-noreport
Try to look inside compressed files, but report information about
the contents only not the compression.
-0, --print0
Output a null character `\0' after the end of the filename. Nice
to cut(1) the output. This does not affect the separator, which
is still printed.
If this option is repeated more than once, then file prints just
the filename followed by a NUL followed by the description (or
ERROR: text) followed by a second NUL for each entry.
--help Print a help message and exit.
ENVIRONMENT
The environment variable MAGIC can be used to set the default magic file
name. If that variable is set, then file will not attempt to open
$HOME/.magic. file adds ".mgc" to the value of this variable as
appropriate. The environment variable POSIXLY_CORRECT controls (on
systems that support symbolic links), whether file will attempt to follow
symlinks or not. If set, then file follows symlink, otherwise it does
not. This is also controlled by the -L and -h options.
FILES
/usr/share/misc/magic.mgc Default compiled list of magic.
/usr/share/misc/magic Directory containing default magic files.
EXIT STATUS
file will exit with 0 if the operation was successful or >0 if an error
was encountered. The following errors cause diagnostic messages, but
don't affect the program exit code (as POSIX requires), unless -E is
specified:
* A file cannot be found
* There is no permission to read a file
* The file type cannot be determined
EXAMPLES
$ file file.c file /dev/{wd0a,hda}
file.c: C program text
file: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV),
dynamically linked (uses shared libs), stripped
/dev/wd0a: block special (0/0)
/dev/hda: block special (3/0)
$ file -s /dev/wd0{b,d}
/dev/wd0b: data
/dev/wd0d: x86 boot sector
$ file -s /dev/hda{,1,2,3,4,5,6,7,8,9,10}
/dev/hda: x86 boot sector
/dev/hda1: Linux/i386 ext2 filesystem
/dev/hda2: x86 boot sector
/dev/hda3: x86 boot sector, extended partition table
/dev/hda4: Linux/i386 ext2 filesystem
/dev/hda5: Linux/i386 swap file
/dev/hda6: Linux/i386 swap file
/dev/hda7: Linux/i386 swap file
/dev/hda8: Linux/i386 swap file
/dev/hda9: empty
/dev/hda10: empty
$ file -i file.c file /dev/{wd0a,hda}
file.c: text/x-c
file: application/x-executable
/dev/hda: application/x-not-regular-file
/dev/wd0a: application/x-not-regular-file
SEE ALSO
hexdump(1), od(1), strings(1), magic(5)
STANDARDS CONFORMANCE
This program is believed to exceed the System V Interface Definition of
FILE(CMD), as near as one can determine from the vague language contained
therein. Its behavior is mostly compatible with the System V program of
the same name. This version knows more magic, however, so it will
produce different (albeit more accurate) output in many cases.
The one significant difference between this version and System V is that
this version treats any white space as a delimiter, so that spaces in
pattern strings must be escaped. For example,
>10 string language impress (imPRESS data)
in an existing magic file would have to be changed to
>10 string language\ impress (imPRESS data)
In addition, in this version, if a pattern string contains a backslash,
it must be escaped. For example
0 string \begindata Andrew Toolkit document
in an existing magic file would have to be changed to
0 string \\begindata Andrew Toolkit document
SunOS releases 3.2 and later from Sun Microsystems include a file command
derived from the System V one, but with some extensions. This version
differs from Sun's only in minor ways. It includes the extension of the
`&' operator, used as, for example,
>16 long&0x7fffffff >0 not stripped
SECURITY
On systems where libseccomp (https://github.com/seccomp/libseccomp) is
available, file is enforces limiting system calls to only the ones
necessary for the operation of the program. This enforcement does not
provide any security benefit when file is asked to decompress input files
running external programs with the -z option. To enable execution of
external decompressors, one needs to disable sandboxing using the -S
option.
MAGIC DIRECTORY
The magic file entries have been collected from various sources, mainly
USENET, and contributed by various authors. Christos Zoulas (address
below) will collect additional or corrected magic file entries. A
consolidation of magic file entries will be distributed periodically.
The order of entries in the magic file is significant. Depending on what
system you are using, the order that they are put together may be
incorrect. If your old file command uses a magic file, keep the old
magic file around for comparison purposes (rename it to
/usr/share/misc/magic.orig).
HISTORY
There has been a file command in every UNIX since at least Research
Version 4 (man page dated November, 1973). The System V version
introduced one significant major change: the external list of magic
types. This slowed the program down slightly but made it a lot more
flexible.
This program, based on the System V version, was written by Ian Darwin
<ian@darwinsys.com> without looking at anybody else's source code.
John Gilmore revised the code extensively, making it better than the
first version. Geoff Collyer found several inadequacies and provided
some magic file entries. Contributions of the `&' operator by Rob
McMahon, <cudcv@warwick.ac.uk>, 1989.
Guy Harris, <guy@netapp.com>, made many changes from 1993 to the present.
Primary development and maintenance from 1990 to the present by Christos
Zoulas <christos@astron.com>.
Altered by Chris Lowth <chris@lowth.com>, 2000: handle the -i option to
output mime type strings, using an alternative magic file and internal
logic.
Altered by Eric Fischer <enf@pobox.com>, July, 2000, to identify
character codes and attempt to identify the languages of non-ASCII files.
Altered by Reuben Thomas <rrt@sc3d.org>, 2007-2011, to improve MIME
support, merge MIME and non-MIME magic, support directories as well as
files of magic, apply many bug fixes, update and fix a lot of magic,
improve the build system, improve the documentation, and rewrite the
Python bindings in pure Python.
The list of contributors to the `magic' directory (magic files) is too
long to include here. You know who you are; thank you. Many
contributors are listed in the source files.
LEGAL NOTICE
Copyright (c) Ian F. Darwin, Toronto, Canada, 1986-1999. Covered by the
standard Berkeley Software Distribution copyright; see the file COPYING
in the source distribution.
The files tar.h and is_tar.c were written by John Gilmore from his
public-domain tar(1) program, and are not covered by the above license.
BUGS
Please report bugs and send patches to the bug tracker at
https://bugs.astron.com/ or the mailing list at <file@astron.com> (visit
https://mailman.astron.com/mailman/listinfo/file first to subscribe).
TODO
Fix output so that tests for MIME and APPLE flags are not needed all over
the place, and actual output is only done in one place. This needs a
design. Suggestion: push possible outputs on to a list, then pick the
last-pushed (most specific, one hopes) value at the end, or use a default
if the list is empty. This should not slow down evaluation.
The handling of MAGIC_CONTINUE and printing \012- between entries is
clumsy and complicated; refactor and centralize.
Some of the encoding logic is hard-coded in encoding.c and can be moved
to the magic files if we had a !:charset annotation.
Continue to squash all magic bugs. See Debian BTS for a good source.
Store arbitrarily long strings, for example for %s patterns, so that they
can be printed out. Fixes Debian bug #271672. This can be done by
allocating strings in a string pool, storing the string pool at the end
of the magic file and converting all the string pointers to relative
offsets from the string pool.
Add syntax for relative offsets after current level (Debian bug #466037).
Make file -ki work, i.e. give multiple MIME types.
Add a zip library so we can peek inside Office2007 documents to print
more details about their contents.
Add an option to print URLs for the sources of the file descriptions.
Combine script searches and add a way to map executable names to MIME
types (e.g. have a magic value for !:mime which causes the resulting
string to be looked up in a table). This would avoid adding the same
magic repeatedly for each new hash-bang interpreter.
When a file descriptor is available, we can skip and adjust the buffer
instead of the hacky buffer management we do now.
Fix "name" and "use" to check for consistency at compile time (duplicate
"name", "use" pointing to undefined "name" ). Make "name" / "use" more
efficient by keeping a sorted list of names. Special-case ^ to flip
endianness in the parser so that it does not have to be escaped, and
document it.
If the offsets specified internally in the file exceed the buffer size (
HOWMANY variable in file.h), then we don't seek to that offset, but we
give up. It would be better if buffer managements was done when the file
descriptor is available so we can seek around the file. One must be
careful though because this has performance and thus security
considerations, because one can slow down things by repeateadly seeking.
There is support now for keeping separate buffers and having offsets from
the end of the file, but the internal buffer management still needs an
overhaul.
AVAILABILITY
You can obtain the original author's latest version by anonymous FTP on
ftp.astron.com in the directory /pub/file/file-X.YZ.tar.gz.
DragonFly 6.1-DEVELOPMENT February 5, 2021 DragonFly 6.1-DEVELOPMENT
file(n) Tcl Built-In Commands file(n)
______________________________________________________________________________
NAME
file - Manipulate file names and attributes
SYNOPSIS
file option name ?arg arg ...?
______________________________________________________________________________
DESCRIPTION
This command provides several operations on a file's name or
attributes. Name is the name of a file; if it starts with a tilde,
then tilde substitution is done before executing the command (see the
manual entry for filename for details). Option indicates what to do
with the file name. Any unique abbreviation for option is acceptable.
The valid options are:
file atime name ?time?
Returns a decimal string giving the time at which file name was
last accessed. If time is specified, it is an access time to
set for the file. The time is measured in the standard POSIX
fashion as seconds from a fixed starting time (often January 1,
1970). If the file does not exist or its access time cannot be
queried or set then an error is generated. On Windows, FAT file
systems do not support access time.
file attributes name
file attributes name ?option?
file attributes name ?option value option value...?
This subcommand returns or sets platform-specific values
associated with a file. The first form returns a list of the
platform-specific options and their values. The second form
returns the value for the given option. The third form sets one
or more of the values. The values are as follows:
On Unix, -group gets or sets the group name for the file. A
group id can be given to the command, but it returns a group
name. -owner gets or sets the user name of the owner of the
file. The command returns the owner name, but the numerical id
can be passed when setting the owner. -permissions retrieves or
sets a file's access permissions, using octal notation by
default. This option also provides limited support for setting
permissions using the symbolic notation accepted by the chmod
command, following the form [ugo]?[[+-=][rwxst],[...]]. Multiple
permission specifications may be given, separated by commas.
E.g., u+s,go-rw would set the setuid bit for a file's owner as
well as remove read and write permission for the file's group
and other users. An ls-style string of the form rwxrwxrwx is
also accepted but must always be 9 characters long. E.g., rwxr-
xr-t is equivalent to 01755. On versions of Unix supporting file
flags, -readonly returns the value of, or sets, or clears the
readonly attribute of a file, i.e., the user immutable flag
(uchg) to the chflags command.
On Windows, -archive gives the value or sets or clears the
archive attribute of the file. -hidden gives the value or sets
or clears the hidden attribute of the file. -longname will
expand each path element to its long version. This attribute
cannot be set. -readonly gives the value or sets or clears the
readonly attribute of the file. -shortname gives a string where
every path element is replaced with its short (8.3) version of
the name. This attribute cannot be set. -system gives or sets or
clears the value of the system attribute of the file.
On Mac OS X and Darwin, -creator gives or sets the Finder
creator type of the file. -hidden gives or sets or clears the
hidden attribute of the file. -readonly gives or sets or clears
the readonly attribute of the file. -rsrclength gives the length
of the resource fork of the file, this attribute can only be set
to the value 0, which results in the resource fork being
stripped off the file.
file channels ?pattern?
If pattern is not specified, returns a list of names of all
registered open channels in this interpreter. If pattern is
specified, only those names matching pattern are returned.
Matching is determined using the same rules as for string match.
file copy ?-force? ?--? source target
file copy ?-force? ?--? source ?source ...? targetDir
The first form makes a copy of the file or directory source
under the pathname target. If target is an existing directory,
then the second form is used. The second form makes a copy
inside targetDir of each source file listed. If a directory is
specified as a source, then the contents of the directory will
be recursively copied into targetDir. Existing files will not be
overwritten unless the -force option is specified (when Tcl will
also attempt to adjust permissions on the destination file or
directory if that is necessary to allow the copy to proceed).
When copying within a single filesystem, file copy will copy
soft links (i.e. the links themselves are copied, not the
things they point to). Trying to overwrite a non-empty
directory, overwrite a directory with a file, or overwrite a
file with a directory will all result in errors even if -force
was specified. Arguments are processed in the order specified,
halting at the first error, if any. A -- marks the end of
switches; the argument following the -- will be treated as a
source even if it starts with a -.
file delete ?-force? ?--? ?pathname ... ?
Removes the file or directory specified by each pathname
argument. Non-empty directories will be removed only if the
-force option is specified. When operating on symbolic links,
the links themselves will be deleted, not the objects they point
to. Trying to delete a non-existent file is not considered an
error. Trying to delete a read-only file will cause the file to
be deleted, even if the -force flags is not specified. If the
-force option is specified on a directory, Tcl will attempt both
to change permissions and move the current directory "pwd" out
of the given path if that is necessary to allow the deletion to
proceed. Arguments are processed in the order specified,
halting at the first error, if any. A -- marks the end of
switches; the argument following the -- will be treated as a
pathname even if it starts with a -.
file dirname name
Returns a name comprised of all of the path components in name
excluding the last element. If name is a relative file name and
only contains one path element, then returns ".". If name
refers to a root directory, then the root directory is returned.
For example,
file dirname c:/
returns c:/.
Note that tilde substitution will only be performed if it is
necessary to complete the command. For example,
file dirname ~/src/foo.c
returns ~/src, whereas
file dirname ~
returns /home (or something similar).
file executable name
Returns 1 if file name is executable by the current user, 0
otherwise. On Windows, which does not have an executable
attribute, the command treats all directories and any files with
extensions exe, com, cmd or bat as executable.
file exists name
Returns 1 if file name exists and the current user has search
privileges for the directories leading to it, 0 otherwise.
file extension name
Returns all of the characters in name after and including the
last dot in the last element of name. If there is no dot in the
last element of name then returns the empty string.
file isdirectory name
Returns 1 if file name is a directory, 0 otherwise.
file isfile name
Returns 1 if file name is a regular file, 0 otherwise.
file join name ?name ...?
Takes one or more file names and combines them, using the
correct path separator for the current platform. If a
particular name is relative, then it will be joined to the
previous file name argument. Otherwise, any earlier arguments
will be discarded, and joining will proceed from the current
argument. For example,
file join a b /foo bar
returns /foo/bar.
Note that any of the names can contain separators, and that the
result is always canonical for the current platform: / for Unix
and Windows.
file link ?-linktype? linkName ?target?
If only one argument is given, that argument is assumed to be
linkName, and this command returns the value of the link given
by linkName (i.e. the name of the file it points to). If
linkName is not a link or its value cannot be read (as, for
example, seems to be the case with hard links, which look just
like ordinary files), then an error is returned.
If 2 arguments are given, then these are assumed to be linkName
and target. If linkName already exists, or if target does not
exist, an error will be returned. Otherwise, Tcl creates a new
link called linkName which points to the existing filesystem
object at target (which is also the returned value), where the
type of the link is platform-specific (on Unix a symbolic link
will be the default). This is useful for the case where the
user wishes to create a link in a cross-platform way, and does
not care what type of link is created.
If the user wishes to make a link of a specific type only, (and
signal an error if for some reason that is not possible), then
the optional -linktype argument should be given. Accepted
values for -linktype are "-symbolic" and "-hard".
On Unix, symbolic links can be made to relative paths, and those
paths must be relative to the actual linkName's location (not to
the cwd), but on all other platforms where relative links are
not supported, target paths will always be converted to
absolute, normalized form before the link is created (and
therefore relative paths are interpreted as relative to the
cwd). Furthermore, "~user" paths are always expanded to
absolute form. When creating links on filesystems that either
do not support any links, or do not support the specific type
requested, an error message will be returned. Most Unix
platforms support both symbolic and hard links (the latter for
files only). Windows supports symbolic directory links and hard
file links on NTFS drives.
file lstat name varName
Same as stat option (see below) except uses the lstat kernel
call instead of stat. This means that if name refers to a
symbolic link the information returned in varName is for the
link rather than the file it refers to. On systems that do not
support symbolic links this option behaves exactly the same as
the stat option.
file mkdir ?dir ...?
Creates each directory specified. For each pathname dir
specified, this command will create all non-existing parent
directories as well as dir itself. If an existing directory is
specified, then no action is taken and no error is returned.
Trying to overwrite an existing file with a directory will
result in an error. Arguments are processed in the order
specified, halting at the first error, if any.
file mtime name ?time?
Returns a decimal string giving the time at which file name was
last modified. If time is specified, it is a modification time
to set for the file (equivalent to Unix touch). The time is
measured in the standard POSIX fashion as seconds from a fixed
starting time (often January 1, 1970). If the file does not
exist or its modified time cannot be queried or set then an
error is generated.
file nativename name
Returns the platform-specific name of the file. This is useful
if the filename is needed to pass to a platform-specific call,
such as to a subprocess via exec under Windows (see EXAMPLES
below).
file normalize name
Returns a unique normalized path representation for the file-
system object (file, directory, link, etc), whose string value
can be used as a unique identifier for it. A normalized path is
an absolute path which has all "../" and "./" removed. Also it
is one which is in the "standard" format for the native
platform. On Unix, this means the segments leading up to the
path must be free of symbolic links/aliases (but the very last
path component may be a symbolic link), and on Windows it also
means we want the long form with that form's case-dependence
(which gives us a unique, case-dependent path). The one
exception concerning the last link in the path is necessary,
because Tcl or the user may wish to operate on the actual
symbolic link itself (for example file delete, file rename, file
copy are defined to operate on symbolic links, not on the things
that they point to).
file owned name
Returns 1 if file name is owned by the current user, 0
otherwise.
file pathtype name
Returns one of absolute, relative, volumerelative. If name
refers to a specific file on a specific volume, the path type
will be absolute. If name refers to a file relative to the
current working directory, then the path type will be relative.
If name refers to a file relative to the current working
directory on a specified volume, or to a specific file on the
current working volume, then the path type is volumerelative.
file readable name
Returns 1 if file name is readable by the current user, 0
otherwise.
file readlink name
Returns the value of the symbolic link given by name (i.e. the
name of the file it points to). If name is not a symbolic link
or its value cannot be read, then an error is returned. On
systems that do not support symbolic links this option is
undefined.
file rename ?-force? ?--? source target
file rename ?-force? ?--? source ?source ...? targetDir
The first form takes the file or directory specified by pathname
source and renames it to target, moving the file if the pathname
target specifies a name in a different directory. If target is
an existing directory, then the second form is used. The second
form moves each source file or directory into the directory
targetDir. Existing files will not be overwritten unless the
-force option is specified. When operating inside a single
filesystem, Tcl will rename symbolic links rather than the
things that they point to. Trying to overwrite a non-empty
directory, overwrite a directory with a file, or a file with a
directory will all result in errors. Arguments are processed in
the order specified, halting at the first error, if any. A --
marks the end of switches; the argument following the -- will be
treated as a source even if it starts with a -.
file rootname name
Returns all of the characters in name up to but not including
the last "." character in the last component of name. If the
last component of name does not contain a dot, then returns
name.
file separator ?name?
If no argument is given, returns the character which is used to
separate path segments for native files on this platform. If a
path is given, the filesystem responsible for that path is asked
to return its separator character. If no file system accepts
name, an error is generated.
file size name
Returns a decimal string giving the size of file name in bytes.
If the file does not exist or its size cannot be queried then an
error is generated.
file split name
Returns a list whose elements are the path components in name.
The first element of the list will have the same path type as
name. All other elements will be relative. Path separators
will be discarded unless they are needed to ensure that an
element is unambiguously relative. For example, under Unix
file split /foo/~bar/baz
returns "/ foo ./~bar baz" to ensure that later commands that
use the third component do not attempt to perform tilde
substitution.
file stat name varName
Invokes the stat kernel call on name, and uses the variable
given by varName to hold information returned from the kernel
call. VarName is treated as an array variable, and the
following elements of that variable are set: atime, ctime, dev,
gid, ino, mode, mtime, nlink, size, type, uid. Each element
except type is a decimal string with the value of the
corresponding field from the stat return structure; see the
manual entry for stat for details on the meanings of the values.
The type element gives the type of the file in the same form
returned by the command file type. This command returns an
empty string.
file system name
Returns a list of one or two elements, the first of which is the
name of the filesystem to use for the file, and the second, if
given, an arbitrary string representing the filesystem-specific
nature or type of the location within that filesystem. If a
filesystem only supports one type of file, the second element
may not be supplied. For example the native files have a first
element "native", and a second element which when given is a
platform-specific type name for the file's system (e.g. "NTFS",
"FAT", on Windows). A generic virtual file system might return
the list "vfs ftp" to represent a file on a remote ftp site
mounted as a virtual filesystem through an extension called
"vfs". If the file does not belong to any filesystem, an error
is generated.
file tail name
Returns all of the characters in the last filesystem component
of name. Any trailing directory separator in name is ignored.
If name contains no separators then returns name. So, file tail
a/b, file tail a/b/ and file tail b all return b.
file tempfile ?nameVar? ?template?
Creates a temporary file and returns a read-write channel opened |
on that file. If the nameVar is given, it specifies a variable |
that the name of the temporary file will be written into; if |
absent, Tcl will attempt to arrange for the temporary file to be |
deleted once it is no longer required. If the template is |
present, it specifies parts of the template of the filename to |
use when creating it (such as the directory, base-name or |
extension) though some platforms may ignore some or all of these |
parts and use a built-in default instead. |
Note that temporary files are only ever created on the native |
filesystem. As such, they can be relied upon to be used with |
operating-system native APIs and external programs that require |
a filename. |
file type name
Returns a string giving the type of file name, which will be one
of file, directory, characterSpecial, blockSpecial, fifo, link,
or socket.
file volumes
Returns the absolute paths to the volumes mounted on the system,
as a proper Tcl list. Without any virtual filesystems mounted
as root volumes, on UNIX, the command will always return "/",
since all filesystems are locally mounted. On Windows, it will
return a list of the available local drives (e.g. "a:/ c:/").
If any virtual filesystem has mounted additional volumes, they
will be in the returned list.
file writable name
Returns 1 if file name is writable by the current user, 0
otherwise.
PORTABILITY ISSUES
Unix
These commands always operate using the real user and group
identifiers, not the effective ones.
Windows
The file owned subcommand uses the user identifier (SID) of the
process token, not the thread token which may be impersonating
some other user.
EXAMPLES
This procedure shows how to search for C files in a given directory
that have a correspondingly-named object file in the current directory:
proc findMatchingCFiles {dir} {
set files {}
switch $::tcl_platform(platform) {
windows {
set ext .obj
}
unix {
set ext .o
}
}
foreach file [glob -nocomplain -directory $dir *.c] {
set objectFile [file tail [file rootname $file]]$ext
if {[file exists $objectFile]} {
lappend files $file
}
}
return $files
}
Rename a file and leave a symbolic link pointing from the old location
to the new place:
set oldName foobar.txt
set newName foo/bar.txt
# Make sure that where we're going to move to exists...
if {![file isdirectory [file dirname $newName]]} {
file mkdir [file dirname $newName]
}
file rename $oldName $newName
file link -symbolic $oldName $newName
On Windows, a file can be "started" easily enough (equivalent to
double-clicking on it in the Explorer interface) but the name passed to
the operating system must be in native format:
exec {*}[auto_execok start] {} [file nativename ~/example.txt]
SEE ALSO
filename(n), open(n), close(n), eof(n), gets(n), tell(n), seek(n),
fblocked(n), flush(n)
KEYWORDS
attributes, copy files, delete files, directory, file, move files,
name, rename files, stat, user
Tcl 8.3 file(n)