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:
-
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.
-
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. 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) 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
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.
-
Unix
- These commands always operate using the real user and group identifiers,
not the effective ones.
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(n), open(n), close(n), eof(n), gets(n), tell(n), seek(n), fblocked(n), flush(n)
attributes, copy files, delete files, directory, file, move files, name, rename files, stat, user