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 man-ual manual
ual 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
doesn't exist or its access time cannot be queried or set then an error is generated. On Win-dows, Windows,
dows, 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 com-mand, command,
mand, 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 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 Macintosh, -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 read-only readonly
only attribute of the file. Note that directories can only be locked if File Sharing is turned
on. -type gives or sets the Finder file type for the file.
file channels ?pat- |
tern? | |
If pattern isn't 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. Match- |
ing 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 tar-get target
get 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 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 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 -marks
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 ?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-exis-tent non-existent
tent 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 ``.'' (or ``:''
on the Macintosh). 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 com-mand. command.
mand. 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.
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 cur-rent current
rent 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, and : for Macintosh.
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 isn't 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 doesn't exist, an error will be returned. Otherwise, Tcl creates a new link called
linkName which points to the existing filesystem object at target, 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 doesn't care what
type of link is created. If the user wishes to make a link of a specific type only, (and sig-nal signal
nal 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". 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. In particular Windows 95, 98 and ME do not sup-port support
port any links at present, but most Unix platforms support both symbolic and hard links (the
latter for files only), MacOS supports symbolic links and Windows NT/2000/XP (on NTFS drives)
support symbolic directory links and hard file links.
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 don't support symbolic links this option
behaves exactly the same as the stat option.
file mkdir dir ?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 speci-fied, specified,
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 doesn't 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 exec under Windows or AppleScript on the Macintosh.
file normalize name
Returns a unique normalised 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 '../', './' removed. Also it is one which is in the ``stan-dard'' ``standard''
dard'' format for the native platform. On MacOS, 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 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 rel-ative relative
ative to the current working directory on a specified volume, or to a specific file on the
current working volume, then the file 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 isn't a symbolic link or its value cannot be read, then an error is returned. On sys-tems systems
tems that don't 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 tar-get, target,
get, 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 nonempty
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 doesn't 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 gen-erated. generated.
erated.
file size name
Returns a decimal string giving the size of file name in bytes. If the file doesn't 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 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 informa-tion information
tion returned from the kernel call. VarName is treated as an array variable, and the follow-ing following
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 mean-ings meanings
ings 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 two elements, the first of which is the name of the filesystem to use for
the file, and the second 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 be null. For example the native files have a first element 'native',
and a second element which is a platform-specific type name for the file's system (e.g.
'NTFS', 'FAT', etc), or possibly the empty string if no further information is available or if
this is not implemented. 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 name after the last directory separator. If name contains no
separators then returns name.
file type name
Returns a string giving the type of file name, which will be one of file, directory, charac-terSpecial, characterSpecial,
terSpecial, blockSpecial, fifo, link, or socket.
file volumes
Returns the absolute paths to the volumes mounted on the system, as a proper Tcl list. On the
Macintosh, this will be a list of the mounted drives, both local and network. N.B. if two
drives have the same name, they will both appear on the volume list, but there is currently no
way, from Tcl, to access any but the first of these drives. 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:/}).
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.
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
Tcl 8.3 file(n)
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