file.n

tcl是工具命令语言

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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
.TP
\fBfile attributes \fIname\fR ?\fBoption\fR?
.TP
\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
.TP
\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.  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 \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 link ?\fI-linktype\fR? \fIlinkName\fR ?\fItarget\fR?
.
If only one argument is given, that argument is assumed to be
\fIlinkName\fR, and this command returns the value of the link given by
\fIlinkName\fR (i.e. the name of the file it points to).  If
\fIlinkName\fR 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 \fIlinkName\fR and
\fItarget\fR. If \fIlinkName\fR already exists, or if \fItarget\fR
doesn't exist, an error will be returned.  Otherwise, Tcl creates a new
link called \fIlinkName\fR which points to the existing filesystem object
at \fItarget\fR, 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
\fI-linktype\fR argument should be given.  Accepted values for