DOKK / manpages / debian 11 / tcl8.6-doc / file.3tcl.en
file(3tcl) Tcl Built-In Commands file(3tcl) 







file - Manipulate file names and attributes








file option name ?arg arg ...?










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:



  

  
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.

  

  

  

  

  

  
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.





  

  
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.

  

  

  

  
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 -.

  

  
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 -.

  

  
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).





  

  
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.

  

  
Returns 1 if file name exists and the current user has
      search privileges for the directories leading to it, 0
    otherwise.

  

  
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.

  

  
Returns 1 if file name is a directory, 0
    otherwise.

  

  
Returns 1 if file name is a regular file, 0
      otherwise.

  

  
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.





  

  
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.





  

  
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.

  

  
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.

  

  
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.

  

  
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).

  

  
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).

  

  
Returns 1 if file name is owned by the current user,
      0 otherwise.

  

  
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.

  

  
Returns 1 if file name is readable by the current user,
      0 otherwise.

  

  
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.

  

  

  

  
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 -.

  

  
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.

  

  
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.

  

  
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.

  

  
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.





  

  
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.

  

  
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.

  

  
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.

  

  
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.





  

  
Returns a string giving the type of file name, which will be one of
      file, directory, characterSpecial,
      blockSpecial, fifo, link, or socket.

  

  
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.

  

  
Returns 1 if file name is writable by the current user,
      0 otherwise.











  

  
These commands always operate using the real user and group identifiers,
      not the effective ones.

  

  
The file owned subcommand uses the user identifier (SID) of the
      process token, not the thread token which may be impersonating some other
      user.










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]










filename(3tcl), open(3tcl), close(3tcl), eof(3tcl), gets(3tcl),
    tell(3tcl), seek(3tcl), fblocked(3tcl), flush(3tcl)








attributes, copy files, delete files, directory, file, move files,
    name, rename files, stat, user







  

    8.3
    Tcl