Cwd - get pathname of current working directory

- NAME
- SYNOPSIS
- DESCRIPTION

- getcwd and friends
- abs_path and friends
- $ENV{PWD}

- NOTES
- AUTHOR
- COPYRIGHT
- SEE ALSO

# 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() function) be used in all code to ensure portability.

By default, it exports the functions cwd(), getcwd(), fastcwd(), and `fastgetcwd()` (and, on Win32, `getdcwd())` 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.

  Re-implements the `getcwd(3)` (or `getwd(3))` functions in Perl.

cwd

          my $cwd = cwd();

  The `cwd()` 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 getcwd(), 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 `fastcwd()` 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 `fastgetcwd()` function is provided as a synonym for cwd().

getdcwd

          my $cwd = getdcwd();
          my $cwd = getdcwd('C:');

  The `getdcwd()` 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 `_getdcwd()` 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 getcwd(). Symbolic links and relative-path components (``.'' and ``..'') are resolved to return the canonical pathname, just like realpath(3).

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

- Since the path seperators are different on some operating systems ('/' on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec modules wherever portability is a concern.

- 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

Originally by the perl5-porters.

Maintained by Ken Williams <KWILLIAMS@cpan.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

the File::chdir manpage

Cwd - get pathname of current working directory