


Cwd(3p)          Perl Programmers Reference Guide         Cwd(3p)


NAME
       Cwd - 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



2001-05-24                 perl v5.6.1                          1





Cwd(3p)          Perl Programmers Reference Guide         Cwd(3p)


       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.




































2001-05-24                 perl v5.6.1                          2


