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a0d0e21e 1package Cwd;
4d6b4052 2require 5.6.0;
a0d0e21e 3
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4=head1 NAME
5
902bacac 6Cwd - get pathname of current working directory
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7
8=head1 SYNOPSIS
9
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10 use Cwd;
11 $dir = cwd;
12
13 use Cwd;
14 $dir = getcwd;
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15
16 use Cwd;
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17 $dir = fastcwd;
18
19 use Cwd;
4633a7c4 20 $dir = fastgetcwd;
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21
22 use Cwd 'chdir';
23 chdir "/tmp";
24 print $ENV{'PWD'};
25
e4c51978 26 use Cwd 'abs_path'; # aka realpath()
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27 print abs_path($ENV{'PWD'});
28
29 use Cwd 'fast_abs_path';
30 print fast_abs_path($ENV{'PWD'});
31
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32=head1 DESCRIPTION
33
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34This module provides functions for determining the pathname of the
35current working directory. By default, it exports the functions
36cwd(), getcwd(), fastcwd(), and fastgetcwd() into the caller's
37namespace. Each of these functions are called without arguments and
38return the absolute path of the current working directory. It is
39recommended that cwd (or another *cwd() function) be used in I<all>
40code to ensure portability.
41
42The cwd() is the most natural and safe form for the current
43architecture. For most systems it is identical to `pwd` (but without
44the trailing line terminator).
45
f06db76b 46The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
4633a7c4 47in Perl.
f06db76b 48
cb1a09d0 49The fastcwd() function looks the same as getcwd(), but runs faster.
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50It's also more dangerous because it might conceivably chdir() you out
51of a directory that it can't chdir() you back into. If fastcwd
52encounters a problem it will return undef but will probably leave you
53in a different directory. For a measure of extra security, if
54everything appears to have worked, the fastcwd() function will check
55that it leaves you in the same directory that it started in. If it has
56changed it will C<die> with the message "Unstable directory path,
57current directory changed unexpectedly". That should never happen.
f06db76b 58
902bacac 59The fastgetcwd() function is provided as a synonym for cwd().
fb73857a 60
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61The abs_path() function takes a single argument and returns the
62absolute pathname for that argument. It uses the same algorithm as
63getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links and
64relative-path components ("." and "..") are resolved to return the
65canonical pathname, just like realpath(3). This function is also
66callable as realpath().
67
68The fast_abs_path() function looks the same as abs_path() but runs
69faster and, like fastcwd(), is more dangerous.
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70
71If you ask to override your chdir() built-in function, then your PWD
72environment variable will be kept up to date. (See
55497cff 73L<perlsub/Overriding Builtin Functions>.) Note that it will only be
1fef88e7 74kept up to date if all packages which use chdir import it from Cwd.
4633a7c4 75
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76=head1 NOTES
77
78=over 4
79
80=item *
81
82On Mac OS (Classic), the path separator is ':', not '/', and the
83current directory is denoted as ':', not '.'. To move up the directory
84tree, you will use '::' to move up one level, but ':::' and so on to
85move up the tree two or more levels (i.e. the equivalent to '../../..'
86is '::::'). Generally, you should be careful about specifying relative pathnames.
87While a full path always begins with a volume name, a relative pathname
88should always begin with a ':'. If specifying a volume name only, a
89trailing ':' is required.
90
91Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()>
92functions are all aliases for the C<cwd()> function, which, on Mac OS,
93calls `pwd`. Likewise, the C<abs_path()> function is an alias for
94C<fast_abs_path()>.
95
96=back
97
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98=cut
99
b060a406 100use strict;
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101
102use Carp;
103
4d6b4052 104our $VERSION = '2.05';
96e4d5b1 105
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106use base qw/ Exporter /;
107our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
108our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
a0d0e21e 109
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110# sys_cwd may keep the builtin command
111
112# All the functionality of this module may provided by builtins,
113# there is no sense to process the rest of the file.
114# The best choice may be to have this in BEGIN, but how to return from BEGIN?
115
116if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) {
117 local $^W = 0;
118 *cwd = \&sys_cwd;
119 *getcwd = \&cwd;
120 *fastgetcwd = \&cwd;
121 *fastcwd = \&cwd;
122 *abs_path = \&sys_abspath;
123 *fast_abs_path = \&abs_path;
124 *realpath = \&abs_path;
125 *fast_realpath = \&abs_path;
126 return 1;
127}
128
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129eval {
130 require XSLoader;
131 XSLoader::load('Cwd');
132};
4633a7c4 133
96e4d5b1 134
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135# Find the pwd command in the expected locations. We assume these
136# are safe. This prevents _backtick_pwd() consulting $ENV{PATH}
137# so everything works under taint mode.
138my $pwd_cmd;
139foreach my $try (qw(/bin/pwd /usr/bin/pwd)) {
140 if( -x $try ) {
141 $pwd_cmd = $try;
142 last;
143 }
144}
145$pwd_cmd ||= 'pwd';
146
147# The 'natural and safe form' for UNIX (pwd may be setuid root)
8b88ae92 148sub _backtick_pwd {
3547aa9a 149 my $cwd = `$pwd_cmd`;
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150 # `pwd` may fail e.g. if the disk is full
151 chomp($cwd) if defined $cwd;
4633a7c4 152 $cwd;
8b88ae92 153}
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154
155# Since some ports may predefine cwd internally (e.g., NT)
156# we take care not to override an existing definition for cwd().
157
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158unless(defined &cwd) {
159 # The pwd command is not available in some chroot(2)'ed environments
4aecb5b5 160 if($^O eq 'MacOS' || grep { -x "$_/pwd" } split(':', $ENV{PATH})) {
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161 *cwd = \&_backtick_pwd;
162 }
163 else {
164 *cwd = \&getcwd;
165 }
166}
a0d0e21e 167
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168# set a reasonable (and very safe) default for fastgetcwd, in case it
169# isn't redefined later (20001212 rspier)
170*fastgetcwd = \&cwd;
748a9306 171
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172# By Brandon S. Allbery
173#
174# Usage: $cwd = getcwd();
175
176sub getcwd
177{
07569ed3 178 abs_path('.');
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179}
180
4633a7c4 181# Keeps track of current working directory in PWD environment var
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182# Usage:
183# use Cwd 'chdir';
184# chdir $newdir;
185
4633a7c4 186my $chdir_init = 0;
a0d0e21e 187
4633a7c4 188sub chdir_init {
3b8e3443 189 if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') {
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190 my($dd,$di) = stat('.');
191 my($pd,$pi) = stat($ENV{'PWD'});
192 if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
4633a7c4 193 $ENV{'PWD'} = cwd();
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194 }
195 }
196 else {
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197 my $wd = cwd();
198 $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32';
199 $ENV{'PWD'} = $wd;
a0d0e21e 200 }
4633a7c4 201 # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
3b8e3443 202 if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {
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203 my($pd,$pi) = stat($2);
204 my($dd,$di) = stat($1);
205 if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
206 $ENV{'PWD'}="$2$3";
207 }
208 }
209 $chdir_init = 1;
210}
211
212sub chdir {
22978713 213 my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir)
3b8e3443 214 $newdir =~ s|///*|/|g unless $^O eq 'MSWin32';
a0d0e21e 215 chdir_init() unless $chdir_init;
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216 my $newpwd;
217 if ($^O eq 'MSWin32') {
218 # get the full path name *before* the chdir()
219 $newpwd = Win32::GetFullPathName($newdir);
220 }
221
4633a7c4 222 return 0 unless CORE::chdir $newdir;
4ffa1610 223
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224 if ($^O eq 'VMS') {
225 return $ENV{'PWD'} = $ENV{'DEFAULT'}
226 }
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227 elsif ($^O eq 'MacOS') {
228 return $ENV{'PWD'} = cwd();
229 }
3b8e3443 230 elsif ($^O eq 'MSWin32') {
4ffa1610 231 $ENV{'PWD'} = $newpwd;
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232 return 1;
233 }
748a9306 234
392d8ab8 235 if ($newdir =~ m#^/#s) {
a0d0e21e 236 $ENV{'PWD'} = $newdir;
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237 } else {
238 my @curdir = split(m#/#,$ENV{'PWD'});
239 @curdir = ('') unless @curdir;
240 my $component;
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241 foreach $component (split(m#/#, $newdir)) {
242 next if $component eq '.';
243 pop(@curdir),next if $component eq '..';
244 push(@curdir,$component);
245 }
246 $ENV{'PWD'} = join('/',@curdir) || '/';
247 }
4633a7c4 248 1;
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249}
250
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251# added function alias for those of us more
252# used to the libc function. --tchrist 27-Jan-00
253*realpath = \&abs_path;
254
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255sub fast_abs_path {
256 my $cwd = getcwd();
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257 require File::Spec;
258 my $path = @_ ? shift : File::Spec->curdir;
e79e61e4 259 CORE::chdir($path) || croak "Cannot chdir to $path:$!";
96e4d5b1 260 my $realpath = getcwd();
e79e61e4 261 CORE::chdir($cwd) || croak "Cannot chdir back to $cwd:$!";
96e4d5b1 262 $realpath;
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263}
264
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265# added function alias to follow principle of least surprise
266# based on previous aliasing. --tchrist 27-Jan-00
267*fast_realpath = \&fast_abs_path;
268
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269
270# --- PORTING SECTION ---
271
272# VMS: $ENV{'DEFAULT'} points to default directory at all times
bd3fa61c 273# 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu
c6538b72 274# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
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275# in the process logical name table as the default device and directory
276# seen by Perl. This may not be the same as the default device
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277# and directory seen by DCL after Perl exits, since the effects
278# the CRTL chdir() function persist only until Perl exits.
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279
280sub _vms_cwd {
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281 return $ENV{'DEFAULT'};
282}
283
284sub _vms_abs_path {
285 return $ENV{'DEFAULT'} unless @_;
286 my $path = VMS::Filespec::pathify($_[0]);
287 croak("Invalid path name $_[0]") unless defined $path;
288 return VMS::Filespec::rmsexpand($path);
4633a7c4 289}
68dc0745 290
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291sub _os2_cwd {
292 $ENV{'PWD'} = `cmd /c cd`;
293 chop $ENV{'PWD'};
294 $ENV{'PWD'} =~ s:\\:/:g ;
295 return $ENV{'PWD'};
296}
297
96e4d5b1 298sub _win32_cwd {
2d7a9237 299 $ENV{'PWD'} = Win32::GetCwd();
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300 $ENV{'PWD'} =~ s:\\:/:g ;
301 return $ENV{'PWD'};
302}
303
304*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
2d7a9237 305 defined &Win32::GetCwd);
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306
307*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
68dc0745 308
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309sub _dos_cwd {
310 if (!defined &Dos::GetCwd) {
311 $ENV{'PWD'} = `command /c cd`;
312 chop $ENV{'PWD'};
313 $ENV{'PWD'} =~ s:\\:/:g ;
314 } else {
315 $ENV{'PWD'} = Dos::GetCwd();
316 }
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317 return $ENV{'PWD'};
318}
319
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320sub _qnx_cwd {
321 $ENV{'PWD'} = `/usr/bin/fullpath -t`;
322 chop $ENV{'PWD'};
323 return $ENV{'PWD'};
324}
325
326sub _qnx_abs_path {
fa921dc6 327 my $path = @_ ? shift : '.';
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328 my $realpath=`/usr/bin/fullpath -t $path`;
329 chop $realpath;
330 return $realpath;
331}
332
ed79a026
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333sub _epoc_cwd {
334 $ENV{'PWD'} = EPOC::getcwd();
335 return $ENV{'PWD'};
336}
337
ac1ad7f0 338{
db376a24 339 no warnings; # assignments trigger 'subroutine redefined' warning
4633a7c4 340
ac1ad7f0 341 if ($^O eq 'VMS') {
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342 *cwd = \&_vms_cwd;
343 *getcwd = \&_vms_cwd;
344 *fastcwd = \&_vms_cwd;
345 *fastgetcwd = \&_vms_cwd;
346 *abs_path = \&_vms_abs_path;
347 *fast_abs_path = \&_vms_abs_path;
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348 }
349 elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
350 # We assume that &_NT_cwd is defined as an XSUB or in the core.
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351 *cwd = \&_NT_cwd;
352 *getcwd = \&_NT_cwd;
353 *fastcwd = \&_NT_cwd;
354 *fastgetcwd = \&_NT_cwd;
355 *abs_path = \&fast_abs_path;
ac1ad7f0
PM
356 }
357 elsif ($^O eq 'os2') {
358 # sys_cwd may keep the builtin command
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359 *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
360 *getcwd = \&cwd;
361 *fastgetcwd = \&cwd;
362 *fastcwd = \&cwd;
363 *abs_path = \&fast_abs_path;
ac1ad7f0 364 }
39e571d4
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365 elsif ($^O eq 'dos') {
366 *cwd = \&_dos_cwd;
367 *getcwd = \&_dos_cwd;
368 *fastgetcwd = \&_dos_cwd;
369 *fastcwd = \&_dos_cwd;
96e4d5b1 370 *abs_path = \&fast_abs_path;
ac1ad7f0 371 }
7438b6ad 372 elsif ($^O =~ m/^(?:qnx|nto)$/ ) {
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373 *cwd = \&_qnx_cwd;
374 *getcwd = \&_qnx_cwd;
375 *fastgetcwd = \&_qnx_cwd;
376 *fastcwd = \&_qnx_cwd;
377 *abs_path = \&_qnx_abs_path;
378 *fast_abs_path = \&_qnx_abs_path;
379 }
4fabb596 380 elsif ($^O eq 'cygwin') {
1cab015a
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381 *getcwd = \&cwd;
382 *fastgetcwd = \&cwd;
383 *fastcwd = \&cwd;
384 *abs_path = \&fast_abs_path;
385 }
ed79a026 386 elsif ($^O eq 'epoc') {
fa6a1c44
OF
387 *cwd = \&_epoc_cwd;
388 *getcwd = \&_epoc_cwd;
ed79a026
OF
389 *fastgetcwd = \&_epoc_cwd;
390 *fastcwd = \&_epoc_cwd;
391 *abs_path = \&fast_abs_path;
392 }
4aecb5b5
JH
393 elsif ($^O eq 'MacOS') {
394 *getcwd = \&cwd;
395 *fastgetcwd = \&cwd;
396 *fastcwd = \&cwd;
397 *abs_path = \&fast_abs_path;
398 }
55497cff 399}
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400
401# package main; eval join('',<DATA>) || die $@; # quick test
402
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4031;
404
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405__END__
406BEGIN { import Cwd qw(:DEFAULT chdir); }
407print join("\n", cwd, getcwd, fastcwd, "");
408chdir('..');
409print join("\n", cwd, getcwd, fastcwd, "");
410print "$ENV{PWD}\n";