Provided by: tcl8.6-doc_8.6.12+dfsg-1build1_all 
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 options and their values.
The second form returns the value for the given 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 retrieves or sets a file's access
permissions, using octal notation by default. This option also provides limited
support for setting permissions using the symbolic notation accepted by the chmod
command, following the form [ugo]?[[+-=][rwxst],[...]]. Multiple permission
specifications may be given, separated by commas. E.g., u+s,go-rw would set the
setuid bit for a file's owner as well as remove read and write permission for the
file's group and other users. An ls-style string of the form rwxrwxrwx is also
accepted but must always be 9 characters long. E.g., rwxr-xr-t is equivalent to
01755. On versions of Unix supporting file flags, -readonly returns the value of,
or sets, or clears the readonly attribute of a file, i.e., the user immutable flag
(uchg) to the chflags command.
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(3tcl), open(3tcl), close(3tcl), eof(3tcl), gets(3tcl), tell(3tcl), seek(3tcl),
fblocked(3tcl), flush(3tcl)
KEYWORDS
attributes, copy files, delete files, directory, file, move files, name, rename files,
stat, user