path: root/doc/file.n

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'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\" RCS: @(#) $Id: file.n,v 1.10 2001/11/10 02:34:57 hobbs Exp $
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.so man.macros
.TH file n 8.3 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
file \- Manipulate file names and attributes
.SH SYNOPSIS
\fBfile \fIoption\fR \fIname\fR ?\fIarg arg ...\fR?
.BE

.SH DESCRIPTION
.PP
This command provides several operations on a file's name or attributes.
\fIName\fR 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
\fBfilename\fR for details).  \fIOption\fR indicates what to do with the
file name.  Any unique abbreviation for \fIoption\fR is acceptable.  The
valid options are:
.TP
\fBfile atime \fIname\fR ?\fBtime\fR?
.
Returns a decimal string giving the time at which file \fIname\fR was last
accessed.  If \fItime\fR 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.
.TP
\fBfile attributes \fIname\fR
.br
\fBfile attributes \fIname\fR ?\fBoption\fR?
.br
\fBfile attributes \fIname\fR ?\fBoption value option value...\fR?
.RS
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:
.PP
On Unix, \fB-group\fR gets or sets the group name for the file. A group id
can be given to the command, but it returns a group name. \fB-owner\fR 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. \fB-permissions\fR 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:
\fBu+s,go\-rw\fR add sticky bit for user, remove read and write
permissions for group and other).  A simplified \fBls\fR style string,
of the form rwxrwxrwx (must be 9 characters), is also supported
(example: \fBrwxr\-xr\-t\fR is equivalent to 01755).
.PP
On Windows, \fB-archive\fR gives the value or sets or clears the
archive attribute of the file. \fB-hidden\fR gives the value or sets
or clears the hidden attribute of the file. \fB-longname\fR will
expand each path element to its long version. This attribute cannot be
set. \fB-readonly\fR gives the value or sets or clears the readonly
attribute of the file. \fB-shortname\fR gives a string where every
path element is replaced with its short (8.3) version of the
name. This attribute cannot be set. \fB-system\fR gives or sets or
clears the value of the system attribute of the file.
.PP
On Macintosh, \fB-creator\fR gives or sets the Finder creator type of
the file. \fB-hidden\fR gives or sets or clears the hidden attribute
of the file. \fB-readonly\fR gives or sets or clears the readonly
attribute of the file. Note that directories can only be locked if
File Sharing is turned on. \fB-type\fR gives or sets the Finder file
type for the file.
.RE
.VS
.TP
\fBfile channels ?\fIpattern\fR?
.
If \fIpattern\fR isn't specified, returns a list of names of all
registered open channels in this interpreter.  If \fIpattern\fR is
specified, only those names matching \fIpattern\fR are returned.  Matching
is determined using the same rules as for \fBstring match\fR.
.VE
.TP
\fBfile copy \fR?\fB\-force\fR? ?\fB\-\|\-\fR? \fIsource\fR \fItarget\fR
.br
\fBfile copy \fR?\fB\-force\fR? ?\fB\-\|\-\fR? \fIsource\fR ?\fIsource\fR ...? \fItargetDir\fR
.RS
The first form makes a copy of the file or directory \fIsource\fR under
the pathname \fItarget\fR. If \fItarget\fR is an existing directory,
then the second form is used.  The second form makes a copy inside
\fItargetDir\fR of each \fIsource\fR file listed.  If a directory is
specified as a \fIsource\fR, then the contents of the directory will be
recursively copied into \fItargetDir\fR. Existing files will not be
overwritten unless the \fB\-force\fR option is specified.  When copying
within a single filesystem, \fIfile copy\fR 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
\fI\-force\fR was specified.  Arguments are processed in the order
specified, halting at the first error, if any.  A \fB\-\|\-\fR marks
the end of switches; the argument following the \fB\-\|\-\fR will be
treated as a \fIsource\fR even if it starts with a \fB\-\fR.
.RE
.TP
\fBfile delete \fR?\fB\-force\fR? ?\fB\-\|\-\fR? \fIpathname\fR ?\fIpathname\fR ... ?
.
Removes the file or directory specified by each \fIpathname\fR argument.
Non-empty directories will be removed only if the \fB\-force\fR option is
specified.  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 \fB\-force\fR flags is not specified.  If the \fB\-force\fR 
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 \fB\-\|\-\fR
marks the end of switches; the argument following the \fB\-\|\-\fR will be
treated as a \fIpathname\fR even if it starts with a \fB\-\fR.
.TP
\fBfile dirname \fIname\fR
Returns a name comprised of all of the path components in \fIname\fR
excluding the last element.  If \fIname\fR is a relative file name and
only contains one path element, then returns ``\fB.\fR'' (or ``\fB:\fR''
on the Macintosh).  If \fIname\fR refers to a root directory, then the
root directory is returned.  For example,
.RS
.CS
\fBfile dirname c:/\fR
.CE
returns \fBc:/\fR. 
.PP
Note that tilde substitution will only be
performed if it is necessary to complete the command. For example,
.CS
\fBfile dirname ~/src/foo.c\fR
.CE
returns \fB~/src\fR, whereas
.CS
\fBfile dirname ~\fR
.CE
returns \fB/home\fR (or something similar).
.RE
.TP
\fBfile executable \fIname\fR
.
Returns \fB1\fR if file \fIname\fR is executable by the current user,
\fB0\fR otherwise.  
.TP
\fBfile exists \fIname\fR
.
Returns \fB1\fR if file \fIname\fR exists and the current user has
search privileges for the directories leading to it, \fB0\fR otherwise.
.TP
\fBfile extension \fIname\fR
.
Returns all of the characters in \fIname\fR after and including the last
dot in the last element of \fIname\fR.  If there is no dot in the last
element of \fIname\fR then returns the empty string.
.TP
\fBfile isdirectory \fIname\fR
.
Returns \fB1\fR if file \fIname\fR is a directory, \fB0\fR otherwise.
.TP
\fBfile isfile \fIname\fR
.
Returns \fB1\fR if file \fIname\fR is a regular file, \fB0\fR otherwise.
.TP
\fBfile join \fIname\fR ?\fIname ...\fR?
.
Takes one or more file names and combines them, using the correct path
separator for the current platform.  If a particular \fIname\fR 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,
.RS
.CS
\fBfile join a b /foo bar\fR
.CE
returns \fB/foo/bar\fR.
.PP
Note that any of the names can contain separators, and that the result
is always canonical for the current platform: \fB/\fR for Unix and
Windows, and \fB:\fR for Macintosh.
.RE
.TP
\fBfile lstat \fIname varName\fR
.
Same as \fBstat\fR option (see below) except uses the \fIlstat\fR
kernel call instead of \fIstat\fR.  This means that if \fIname\fR
refers to a symbolic link the information returned in \fIvarName\fR
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 \fBstat\fR option.
.TP
\fBfile mkdir \fIdir\fR ?\fIdir\fR ...?
.
Creates each directory specified.  For each pathname \fIdir\fR specified,
this command will create all non-existing parent directories as
well as \fIdir\fR 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.
.TP
\fBfile mtime \fIname\fR ?\fItime\fR?
.
Returns a decimal string giving the time at which file \fIname\fR was last
modified.  If \fItime\fR is specified, it is a modification time to set for
the file (equivalent to Unix \fBtouch\fR).  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.
.TP
\fBfile nativename \fIname\fR
.
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.
.TP
\fBfile normalize \fIname\fR
.
Returns a unique normalised path representation for the file, whose string
value can be used as a unique identifier for the it.  A normalized path is
one which has all '../', './' removed.  Also it is one which is in the
\'standard\' format for the native platform.  On MacOS, Unix, this means the
path must be free of symbolic links/aliases, and on Windows it means we want
the long form, with the long form's case-dependence (which gives us a
unique, case-dependent path).
.TP
\fBfile owned \fIname\fR 
.
Returns \fB1\fR if file \fIname\fR is owned by the current user, \fB0\fR
otherwise.
.TP
\fBfile pathtype \fIname\fR
.
Returns one of \fBabsolute\fR, \fBrelative\fR, \fBvolumerelative\fR.  If
\fIname\fR refers to a specific file on a specific volume, the path type
will be \fBabsolute\fR.  If \fIname\fR refers to a file relative to the
current working directory, then the path type will be \fBrelative\fR.  If
\fIname\fR 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 \fBvolumerelative\fR.
.TP
\fBfile readable \fIname\fR
.
Returns \fB1\fR if file \fIname\fR is readable by the current user,
\fB0\fR otherwise. 
.TP
\fBfile readlink \fIname\fR
.
Returns the value of the symbolic link given by \fIname\fR (i.e. the name
of the file it points to).  If \fIname\fR 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.
.PP
\fBfile rename \fR?\fB\-force\fR? ?\fB\-\|\-\fR? \fIsource\fR \fItarget\fR
.br
\fBfile rename \fR?\fB\-force\fR? ?\fB\-\|\-\fR? \fIsource\fR ?\fIsource\fR ...? \fItargetDir\fR
.RS
The first form takes the file or directory specified by pathname
\fIsource\fR and renames it to \fItarget\fR, moving the file if the
pathname \fItarget\fR specifies a name in a different directory.  If
\fItarget\fR is an existing directory, then the second form is used.  The
second form moves each \fIsource\fR file or directory into the directory
\fItargetDir\fR.  Existing files will not be overwritten unless the
\fB\-force\fR option is specified.  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 \fB\-\|\-\fR marks the end of
switches; the argument following the \fB\-\|\-\fR will be treated as a
\fIsource\fR even if it starts with a \fB\-\fR.
.RE
.TP
\fBfile rootname \fIname\fR
.
Returns all of the characters in \fIname\fR up to but not including the
last ``.'' character in the last component of name.  If the last
component of \fIname\fR doesn't contain a dot, then returns \fIname\fR.
.TP
\fBfile separator ?\fIname\fR?
.
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 \fIname\fR, an error
is generated.
.TP
\fBfile size \fIname\fR
.
Returns a decimal string giving the size of file \fIname\fR in bytes.  If
the file doesn't exist or its size cannot be queried then an error is
generated.
.TP
\fBfile split \fIname\fR
.
Returns a list whose elements are the path components in \fIname\fR.  The
first element of the list will have the same path type as \fIname\fR.
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
.RS
.CS
\fBfile split /foo/~bar/baz\fR
.CE
returns \fB/\0\0foo\0\0./~bar\0\0baz\fR to ensure that later commands
that use the third component do not attempt to perform tilde
substitution.
.RE
.TP
\fBfile stat  \fIname varName\fR
.
Invokes the \fBstat\fR kernel call on \fIname\fR, and uses the variable
given by \fIvarName\fR to hold information returned from the kernel call.
\fIVarName\fR is treated as an array variable, and the following elements
of that variable are set: \fBatime\fR, \fBctime\fR, \fBdev\fR, \fBgid\fR,
\fBino\fR, \fBmode\fR, \fBmtime\fR, \fBnlink\fR, \fBsize\fR, \fBtype\fR,
\fBuid\fR.  Each element except \fBtype\fR is a decimal string with the
value of the corresponding field from the \fBstat\fR return structure;
see the manual entry for \fBstat\fR for details on the meanings of the
values.  The \fBtype\fR element gives the type of the file in the same
form returned by the command \fBfile type\fR.  This command returns an
empty string.
.TP
\fBfile system \fIname\fR
.
Returns a list of two elements, the first of which is the name of the
filesystem to use for the file, and the second the type of the file
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 (e.g. 'networked'), or
possibly the empty string.  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.
.TP
\fBfile tail \fIname\fR
.
Returns all of the characters in \fIname\fR after the last directory
separator.  If \fIname\fR contains no separators then returns
\fIname\fR.
.TP
\fBfile type \fIname\fR
.
Returns a string giving the type of file \fIname\fR, which will be one of
\fBfile\fR, \fBdirectory\fR, \fBcharacterSpecial\fR, \fBblockSpecial\fR,
\fBfifo\fR, \fBlink\fR, or \fBsocket\fR.
.TP
\fBfile volume\fR
. 
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:/}).
.TP
\fBfile writable \fIname\fR
.
Returns \fB1\fR if file \fIname\fR is writable by the current user,
\fB0\fR otherwise.
.SH "PORTABILITY ISSUES"
.TP
\fBUnix\fR\0\0\0\0\0\0\0
.
These commands always operate using the real user and group identifiers,
not the effective ones. 

.SH "SEE ALSO"
filename(n), open(n), close(n), eof(n), gets(n), tell(n), seek(n),
fblocked(n), flush(n)

.SH KEYWORDS
attributes, copy files, delete files, directory, file, move files, name, rename files, stat