file

file(n)                      Tcl Built-In Commands                     file(n)



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NAME
       file - Manipulate file names and attributes

SYNOPSIS
       file option name ?arg arg ...?
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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 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
              retrieves the octal code that chmod(1) uses.  This command does
              also has limited support for setting using the symbolic
              attributes 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
              versions 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
              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)