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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 at-
       tributes.  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 associ-
	      ated  with a file. The first form	returns	a list of the platform
	      specific flags and their values. The  second  form  returns  the
	      value  for  the specific 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 sets  or  re-
	      trieves  the  octal  code	that chmod(1) uses.  This command does
	      also has limited support for  setting  using  the	 symbolic  at-
	      tributes	for  chmod(1), of the form [ugo]?[[+-=][rwxst],[...]],
	      where multiple symbolic attributes can be	 separated  by	commas
	      (example:	 u+s,go-rw  add	 sticky	 bit for user, remove read and
	      write permissions	for group and other).  A simplified  ls	 style
	      string,  of  the	form rwxrwxrwx (must be	9 characters), is also
	      supported	(example: rwxr-xr-t is equivalent to 01755).  On  ver-
	      sions  of	 Unix supporting file flags, -readonly gives the value
	      or sets or clears	the readonly attribute of the file,  i.e.  the
	      user immutable flag uchg to chflags(1).

	      On  Windows,  -archive gives the value or	sets or	clears the ar-
	      chive 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 cre-
	      ator type	of the file. -hidden gives or sets or clears the  hid-
	      den 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 reg-
	      istered open channels in this interpreter.  If pattern is	speci-
	      fied,  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  un-
	      der  the	pathname  target.  If target is	an existing directory,
	      then the second form is used.  The second	form makes a copy  in-
	      side  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	direc-
	      tory, 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 argu-
	      ment.  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, halt-
	      ing 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 oth-
	      erwise. 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 cor-
	      rect 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  dis-
	      carded, 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 ex-
	      ample, 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 ob-
	      ject  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 val-
	      ues 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 abso-
	      lute, normalized form before the link is created (and  therefore
	      relative	paths  are  interpreted	as relative to the cwd).  Fur-
	      thermore,	"~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 er-
	      ror  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 sym-
	      bolic link the information returned in varName is	for  the  link
	      rather  than the file it refers to.  On systems that do not sup-
	      port symbolic links this option behaves exactly the same as  the
	      stat option.

       file mkdir ?dir ...?
	      Creates  each directory specified.  For each pathname dir	speci-
	      fied, this command will create all non-existing parent  directo-
	      ries  as well as dir itself.  If an existing directory is	speci-
	      fied, 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 ex-
	      ist 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 be-
	      low).

       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	 plat-
	      form.   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 con-
	      cerning 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	other-
	      wise.

       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 cur-
	      rent 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	other-
	      wise.

       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 sys-
	      tems  that  do  not  support symbolic links this option is unde-
	      fined.

       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 tar-
	      getDir. 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 re-
	      sult 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 ele-
	      ment 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 substi-
	      tution.

       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  follow-
	      ing  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 ele-
	      ment 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 tempdir ?template?
	      Creates a	temporary directory (guaranteed	to  be	newly  created |
	      and  writable  by	 the  current script) and returns its name. If |
	      template is given, it specifies one of or	both of	 the  existing |
	      directory	 (on  a	filesystem controlled by the operating system) |
	      to contain the temporary directory, and the base part of the di- |
	      rectory  name;  it is considered to have the location of the di- |
	      rectory if there is a directory separator	in the name,  and  the |
	      base  part  is everything	after the last directory separator (if |
	      non-empty).  The default containing directory is	determined  by |
	      system-specific  operations, and the default base	name prefix is |
	      "tcl".							       |

	      The following output is typical  and  illustrative;  the	actual |
	      output will vary between platforms:			       |

		     % file tempdir					       |
		     /var/tmp/tcl_u0kuy5				       |
		      %	file tempdir /tmp/myapp				       |
		     /tmp/myapp_8o7r9L					       |
		     % file tempdir /tmp/				       |
		     /tmp/tcl_1mOJHD					       |
		     % file tempdir myapp				       |
		     /var/tmp/myapp_0ihS0n				       |

       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 ab- |
	      sent, 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	exten- |
	      sion) 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 op- |
	      erating-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	other-
	      wise.

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  dou-
       ble-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)

NAME | SYNOPSIS | DESCRIPTION | PORTABILITY ISSUES | EXAMPLES | SEE ALSO | KEYWORDS

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