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 doesn't 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 spe-
cific flags and their values. The second form returns the value for the specific option. The third form sets one or more of the val-
ues. 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 sup-
port 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 equiv-
alent 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. -read-
only 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 readonly 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 ?pattern? |
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. 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 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 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-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 ``.'' (or ``:'' on the Macintosh). If name refers to a root directory, then the root direc-
tory 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.
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 join-
ing 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. Other-
wise, 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 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". 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 support 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 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 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 ``standard'' 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 relative 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 systems 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 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 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 generated.
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 unambigu-
ously 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 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, characterSpecial, 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)