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File::Spec(3pm) Perl Programmers Reference Guide File::Spec(3pm)

NAME

File::Spec - portably perform operations on file names

SYNOPSIS

use File::Spec;

$x=File::Spec->catfile('a', 'b', 'c');

which returns 'a/b/c' under Unix. Or:

use File::Spec::Functions;

$x = catfile('a', 'b', 'c');

DESCRIPTION

This module is designed to support operations commonly performed on

file specifications (usually called "file names", but not to be con-

fused with the contents of a file, or Perl's file handles), such as concatenating several directory and file names into a single path, or determining whether a path is rooted. It is based on code directly taken from MakeMaker 5.17, code written by Andreas Koenig, Andy Dougherty, Charles Bailey, Ilya Zakharevich, Paul Schinder, and others. Since these functions are different for most operating systems, each

set of OS specific routines is available in a separate module, includ-

ing:

File::Spec::Unix

File::Spec::Mac

File::Spec::OS2

File::Spec::Win32

File::Spec::VMS

The module appropriate for the current OS is automatically loaded by

File::Spec. Since some modules (like VMS) make use of facilities avail-

able only under that OS, it may not be possible to load all modules under all operating systems.

Since File::Spec is object oriented, subroutines should not be called

directly, as in:

File::Spec::catfile('a','b');

but rather as class methods:

File::Spec->catfile('a','b');

For simple uses, File::Spec::Functions provides convenient functional

forms of these methods. MMEETTHHOODDSS canonpath No physical check on the filesystem, but a logical cleanup of a path.

$cpath = File::Spec->canonpath( $path ) ;

Note that this does *not* collapse x/../y sections into y. This is by design. If /foo on your system is a symlink to /bar/baz, then

/foo/../quux is actually /bar/quux, not /quux as a naive ../-removal

would give you. If you want to do this kind of processing, you prob-

ably want "Cwd"'s "realpath()" function to actually traverse the filesystem cleaning up paths like this. catdir

Concatenate two or more directory names to form a complete path end-

ing with a directory. But remove the trailing slash from the result-

ing string, because it doesn't look good, isn't necessary and con-

fuses OS/2. Of course, if this is the root directory, don't cut off

the trailing slash :-)

$path = File::Spec->catdir( @directories );

catfile

Concatenate one or more directory names and a filename to form a com-

plete path ending with a filename

$path = File::Spec->catfile( @directories, $filename );

curdir Returns a string representation of the current directory.

$curdir = File::Spec->curdir();

devnull Returns a string representation of the null device.

$devnull = File::Spec->devnull();

rootdir Returns a string representation of the root directory.

$rootdir = File::Spec->rootdir();

tmpdir Returns a string representation of the first writable directory from

a list of possible temporary directories. Returns the current direc-

tory if no writable temporary directories are found. The list of

directories checked depends on the platform; e.g. File::Spec::Unix

checks $ENV{TMPDIR} (unless taint is on) and /tmp.

$tmpdir = File::Spec->tmpdir();

updir Returns a string representation of the parent directory.

$updir = File::Spec->updir();

noupwards Given a list of file names, strip out those that refer to a parent

directory. (Does not strip symlinks, only '.', '..', and equiva-

lents.)

@paths = File::Spec->noupwards( @paths );

casetolerant

Returns a true or false value indicating, respectively, that alpha-

betic case is not or is significant when comparing file specifica-

tions.

$iscasetolerant = File::Spec->casetolerant();

filenameisabsolute Takes as its argument a path, and returns true if it is an absolute path.

$isabsolute = File::Spec->filenameisabsolute( $path );

This does not consult the local filesystem on Unix, Win32, OS/2, or Mac OS (Classic). It does consult the working environment for VMS

(see "filenameisabsolute" in File::Spec::VMS).

path Takes no argument. Returns the environment variable "PATH" (or the local platform's equivalent) as a list.

@PATH = File::Spec->path();

join join is the same as catfile. splitpath

Splits a path in to volume, directory, and filename portions. On sys-

tems with no concept of volume, returns '' for volume.

($volume,$directories,$file) = File::Spec->splitpath( $path );

($volume,$directories,$file) = File::Spec->splitpath( $path, $nofile );

For systems with no syntax differentiating filenames from directo-

ries, assumes that the last file is a path unless $nofile is true or

a trailing separator or /. or /.. is present. On Unix, this means

that $nofile true makes this return ( '', $path, '' ).

The directory portion may or may not be returned with a trailing '/'.

The results can be passed to "catpath()" to get back a path equiva-

lent to (usually identical to) the original path. splitdir The opposite of "catdir()".

@dirs = File::Spec->splitdir( $directories );

$directories must be only the directory portion of the path on sys-

tems that have the concept of a volume or that have path syntax that differentiates files from directories.

Unlike just splitting the directories on the separator, empty direc-

tory names ('') can be returned, because these are significant on some OSes. catpath() Takes volume, directory and file portions and returns an entire path.

Under Unix, $volume is ignored, and directory and file are concate-

nated. A '/' is inserted if need be. On other OSes, $volume is sig-

nificant.

$fullpath = File::Spec->catpath( $volume, $directory, $file );

abs2rel Takes a destination path and an optional base path returns a relative path from the base path to the destination path:

$relpath = File::Spec->abs2rel( $path ) ;

$relpath = File::Spec->abs2rel( $path, $base ) ;

If $base is not present or '', then cwd() is used. If $base is rela-

tive, then it is converted to absolute form using "rel2abs()". This means that it is taken to be relative to cwd().

On systems with the concept of volume, if $path and $base appear to

be on two different volumes, we will not attempt to resolve the two

paths, and we will instead simply return $path. Note that previous

versions of this module ignored the volume of $base, which resulted

in garbage results part of the time. On systems that have a grammar that indicates filenames, this ignores

the $base filename as well. Otherwise all path components are assumed

to be directories.

If $path is relative, it is converted to absolute form using

"rel2abs()". This means that it is taken to be relative to cwd().

No checks against the filesystem are made. On VMS, there is interac-

tion with the working environment, as logicals and macros are expanded. Based on code written by Shigio Yamaguchi. rel2abs() Converts a relative path to an absolute path.

$abspath = File::Spec->rel2abs( $path ) ;

$abspath = File::Spec->rel2abs( $path, $base ) ;