Cwd(3pm) Perl Programmers Reference Guide Cwd(3pm)
NAME
Cwd - get pathname of current working directory
SYNOPSIS
use Cwd;
my $dir = getcwd;
use Cwd 'abs_path';
my $abs_path = abs_path($file);
DESCRIPTION
This module provides functions for determining the pathname of the
current working directory. It is recommended that getcwd (or another
*Cwd(3) function) be used in all code to ensure portability.
By default, it exports the functions Cwd(3), Cwd(3), Cwd(3), and
Cwd(3) (and, on Win32, Cwd(3)) into the caller's namespace.
getcwd and friends
Each of these functions are called without arguments and return the
absolute path of the current working directory.
getcwd
my $cwd = getcwd();
Returns the current working directory. On error returns "undef",
with $! set to indicate the error.
Exposes the POSIX function Cwd(3) or re-implements it if it's
not available.
cwd
my $cwd = cwd();
The Cwd(3) is the most natural form for the current architecture.
For most systems it is identical to `pwd` (but without the trailing
line terminator).
fastcwd
my $cwd = fastcwd();
A more dangerous version of Cwd(3), but potentially faster.
It might conceivably chdir() you out of a directory that it can't
chdir() you back into. If fastcwd encounters a problem it will
return undef but will probably leave you in a different directory.
For a measure of extra security, if everything appears to have
worked, the Cwd(3) function will check that it leaves you in the
same directory that it started in. If it has changed it will "die"
with the message "Unstable directory path, current directory
changed unexpectedly". That should never happen.
fastgetcwd
my $cwd = fastgetcwd();
The Cwd(3) function is provided as a synonym for Cwd(3).
getdcwd
my $cwd = getdcwd();
my $cwd = getdcwd('C:');
The Cwd(3) function is also provided on Win32 to get the current
working directory on the specified drive, since Windows maintains a
separate current working directory for each drive. If no drive is
specified then the current drive is assumed.
This function simply calls the Microsoft C library Cwd(3)
function.
abs_path and friends
These functions are exported only on request. They each take a single
argument and return the absolute pathname for it. If no argument is
given they'll use the current working directory.
abs_path
my $abs_path = abs_path($file);
Uses the same algorithm as Cwd(3). Symbolic links and relative-
path components ("." and "..") are resolved to return the canonical
pathname, just like realpath(3). On error returns "undef", with $!
set to indicate the error.
realpath
my $abs_path = realpath($file);
A synonym for abs_path().
fast_abs_path
my $abs_path = fast_abs_path($file);
A more dangerous, but potentially faster version of abs_path.
$ENV{PWD}
If you ask to override your chdir() built-in function,
use Cwd qw(chdir);
then your PWD environment variable will be kept up to date. Note that
it will only be kept up to date if all packages which use chdir import
it from Cwd.
NOTES
o Since the path separators are different on some operating systems
('/' on Unix, ':' on MacPerl, etc...) we recommend you use the
File::Spec modules wherever portability is a concern.
o Actually, on Mac OS, the getcwd(), fastgetcwd() and fastcwd()
functions are all aliases for the cwd() function, which, on Mac OS,
calls `pwd`. Likewise, the abs_path() function is an alias for
fast_abs_path().
AUTHOR
Maintained by perl5-porters <perl5-porters@perl.org>.
COPYRIGHT
Copyright (c) 2004 by the Perl 5 Porters. All rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
Portions of the C code in this library are copyright (c) 1994 by the
Regents of the University of California. All rights reserved. The
license on this code is compatible with the licensing of the rest of
the distribution - please see the source code in Cwd.xs for the
details.
SEE ALSO
File::chdir(3)
perl v5.38.2 2023-11-28 Cwd(3pm)
perl 5.38.2 - Generated Wed Dec 4 15:57:53 CST 2024