Cwd(3) Perl Programmers Reference Guide Cwd(3)NAMECwd - get pathname of current working directory
SYNOPSIS
use Cwd;
$dir = cwd;
use Cwd;
$dir = getcwd;
use Cwd;
$dir = fastcwd;
use Cwd;
$dir = fastgetcwd;
use Cwd 'chdir';
chdir "/tmp";
print $ENV{'PWD'};
use Cwd 'abs_path'; # aka realpath()
print abs_path($ENV{'PWD'});
use Cwd 'fast_abs_path';
print fast_abs_path($ENV{'PWD'});
DESCRIPTION
This module provides functions for determining the path
name of the current working directory. By default, it
exports the functions cwd(), getcwd(), fastcwd(), and
fastgetcwd() into the caller's namespace. Each of these
functions are called without arguments and return the
absolute path of the current working directory. It is
recommended that cwd (or another *cwd() function) be used
in all code to ensure portability.
The cwd() is the most natural and safe form for the cur
rent architecture. For most systems it is identical to
`pwd` (but without the trailing line terminator).
The getcwd() function re-implements the getcwd(3) (or
getwd(3)) functions in Perl.
The fastcwd() function looks the same as getcwd(), but
runs faster. It's also more dangerous because 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 differ
ent directory. For a measure of extra security, if every
thing 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 mes
sage "Unstable directory path, current directory changed
unexpectedly". That should never happen.
The fastgetcwd() function is provided as a synonym for
cwd().
The abs_path() function takes a single argument and
returns the absolute pathname for that argument. It uses
the same algorithm as getcwd(). (Actually, getcwd() is
abs_path(".")) Symbolic links and relative-path compo
nents ("." and "..") are resolved to return the canonical
pathname, just like realpath(3). This function is also
callable as realpath().
The fast_abs_path() function looks the same as abs_path()
but runs faster and, like fastcwd(), is more dangerous.
If you ask to override your chdir() built-in function,
then your PWD environment variable will be kept up to
date. (See the Overriding Builtin Functions entry in the
perlsub manpage.) Note that it will only be kept up to
date if all packages which use chdir import it from Cwd.
2001-02-22 perl v5.6.1 Cwd(3)
