Ubuntu Manpage: file - Manipulate file names and attributes

NAME

       file - Manipulate file names and attributes

SYNOPSIS

       file option name ?arg arg ...?
_________________________________________________________________

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 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 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.

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 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 ?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 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. Otherwise, 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
values 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.

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 '../', './' 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 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 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 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 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 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.

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

KEYWORDS