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
-
Returns a decimal string giving the time at which file name
was last accessed. 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 then an
error is generated.
- 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 ``.'' (or ``:''
on the Macintosh). 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.
Under UNIX this command uses the real user and group identifiers,
not the effective ones.
- 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, and : for Macintosh.
- 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 mtime name
-
Returns a decimal string giving the time at which file name
was last modified. 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 then an
error is generated.
- 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 file type is volumerelative.
- file readable name
-
Returns 1 if file name is readable by
the current user, 0 otherwise.
Under UNIX this command uses the real user and group identifiers,
not the effective ones.
- 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 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 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 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 writable name
-
Returns 1 if file name is writable by
the current user, 0 otherwise.
Under UNIX this command uses the real user and group identifiers,
not the effective ones.
filename
attributes, directory, file, name, stat
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.
Copyright © 1995, 1996 Roger E. Critchlow Jr.