1File::Spec::Mac(3pm) Perl Programmers Reference Guide File::Spec::Mac(3pm)
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6 File::Spec::Mac - File::Spec for Mac OS (Classic)
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9 require File::Spec::Mac; # Done internally by File::Spec if needed
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12 Methods for manipulating file specifications.
13
15 canonpath
16 On Mac OS, there's nothing to be done. Returns what it's given.
17 catdir()
19 Concatenate two or more directory names to form a path separated by
20 colons (":") ending with a directory. Resulting paths are relative by
21 default, but can be forced to be absolute (but avoid this, see
22 below). Automatically puts a trailing ":" on the end of the complete
23 path, because that's what's done in MacPerl's environment and helps
24 to distinguish a file path from a directory path.
25 IMPORTANT NOTE: Beginning with version 1.3 of this module, the
27 resulting path is relative by default and not absolute. This decision
28 was made due to portability reasons. Since "File::Spec->catdir()"
29 returns relative paths on all other operating systems, it will now
30 also follow this convention on Mac OS. Note that this may break some
31 existing scripts.
32 The intended purpose of this routine is to concatenate directory
34 names. But because of the nature of Macintosh paths, some additional
35 possibilities are allowed to make using this routine give reasonable
36 results for some common situations. In other words, you are also
37 allowed to concatenate paths instead of directory names (strictly
38 speaking, a string like ":a" is a path, but not a name, since it
39 contains a punctuation character ":").
40 So, beside calls like
42 catdir("a") = ":a:"
44 catdir("a","b") = ":a:b:"
45 catdir() = "" (special case)
46 calls like the following
48 catdir(":a:") = ":a:"
50 catdir(":a","b") = ":a:b:"
51 catdir(":a:","b") = ":a:b:"
52 catdir(":a:",":b:") = ":a:b:"
53 catdir(":") = ":"
54 are allowed.
56 Here are the rules that are used in "catdir()"; note that we try to
58 be as compatible as possible to Unix:
59 1.
61 The resulting path is relative by default, i.e. the resulting path
62 will have a leading colon.
63 2.
65 A trailing colon is added automatically to the resulting path, to
66 denote a directory.
67 3.
69 Generally, each argument has one leading ":" and one trailing ":"
70 removed (if any). They are then joined together by a ":". Special
71 treatment applies for arguments denoting updir paths like "::lib:",
72 see (4), or arguments consisting solely of colons ("colon paths"),
73 see (5).
74 4.
76 When an updir path like ":::lib::" is passed as argument, the
77 number of directories to climb up is handled correctly, not
78 removing leading or trailing colons when necessary. E.g.
79 catdir(":::a","::b","c") = ":::a::b:c:"
81 catdir(":::a::","::b","c") = ":::a:::b:c:"
82 5.
84 Adding a colon ":" or empty string "" to a path at any position
85 doesn't alter the path, i.e. these arguments are ignored. (When a
86 "" is passed as the first argument, it has a special meaning, see
87 (6)). This way, a colon ":" is handled like a "." (curdir) on Unix,
88 while an empty string "" is generally ignored (see
89 "Unix->canonpath()" ). Likewise, a "::" is handled like a ".."
90 (updir), and a ":::" is handled like a "../.." etc. E.g.
91 catdir("a",":",":","b") = ":a:b:"
93 catdir("a",":","::",":b") = ":a::b:"
94 6.
96 If the first argument is an empty string "" or is a volume name,
97 i.e. matches the pattern /^[^:]+:/, the resulting path is absolute.
98 7.
100 Passing an empty string "" as the first argument to "catdir()" is
101 like passing"File::Spec->rootdir()" as the first argument, i.e.
102 catdir("","a","b") is the same as
104 catdir(rootdir(),"a","b").
106 This is true on Unix, where "catdir("","a","b")" yields "/a/b" and
108 "rootdir()" is "/". Note that "rootdir()" on Mac OS is the startup
109 volume, which is the closest in concept to Unix' "/". This should
110 help to run existing scripts originally written for Unix.
111 8.
113 For absolute paths, some cleanup is done, to ensure that the volume
114 name isn't immediately followed by updirs. This is invalid, because
115 this would go beyond "root". Generally, these cases are handled
116 like their Unix counterparts:
117 Unix:
119 Unix->catdir("","") = "/"
120 Unix->catdir("",".") = "/"
121 Unix->catdir("","..") = "/" # can't go beyond root
122 Unix->catdir("",".","..","..","a") = "/a"
123 Mac:
124 Mac->catdir("","") = rootdir() # (e.g. "HD:")
125 Mac->catdir("",":") = rootdir()
126 Mac->catdir("","::") = rootdir() # can't go beyond root
127 Mac->catdir("",":","::","::","a") = rootdir() . "a:" # (e.g. "HD:a:")
128 However, this approach is limited to the first arguments following
130 "root" (again, see "Unix->canonpath()" ). If there are more
131 arguments that move up the directory tree, an invalid path going
132 beyond root can be created.
133 As you've seen, you can force "catdir()" to create an absolute path
135 by passing either an empty string or a path that begins with a volume
136 name as the first argument. However, you are strongly encouraged not
137 to do so, since this is done only for backward compatibility. Newer
138 versions of File::Spec come with a method called "catpath()" (see
139 below), that is designed to offer a portable solution for the
140 creation of absolute paths. It takes volume, directory and file
141 portions and returns an entire path. While "catdir()" is still
142 suitable for the concatenation of directory names, you are encouraged
143 to use "catpath()" to concatenate volume names and directory paths.
144 E.g.
145 $dir = File::Spec->catdir("tmp","sources");
147 $abs_path = File::Spec->catpath("MacintoshHD:", $dir,"");
148 yields
150 "MacintoshHD:tmp:sources:" .
152 catfile
154 Concatenate one or more directory names and a filename to form a
155 complete path ending with a filename. Resulting paths are relative by
156 default, but can be forced to be absolute (but avoid this).
157 IMPORTANT NOTE: Beginning with version 1.3 of this module, the
159 resulting path is relative by default and not absolute. This decision
160 was made due to portability reasons. Since "File::Spec->catfile()"
161 returns relative paths on all other operating systems, it will now
162 also follow this convention on Mac OS. Note that this may break some
163 existing scripts.
164 The last argument is always considered to be the file portion. Since
166 "catfile()" uses "catdir()" (see above) for the concatenation of the
167 directory portions (if any), the following with regard to relative
168 and absolute paths is true:
169 catfile("") = ""
171 catfile("file") = "file"
172 but
174 catfile("","") = rootdir() # (e.g. "HD:")
176 catfile("","file") = rootdir() . file # (e.g. "HD:file")
177 catfile("HD:","file") = "HD:file"
178 This means that "catdir()" is called only when there are two or more
180 arguments, as one might expect.
181 Note that the leading ":" is removed from the filename, so that
183 catfile("a","b","file") = ":a:b:file" and
185 catfile("a","b",":file") = ":a:b:file"
187 give the same answer.
189 To concatenate volume names, directory paths and filenames, you are
191 encouraged to use "catpath()" (see below).
192 curdir
194 Returns a string representing the current directory. On Mac OS, this
195 is ":".
196 devnull
198 Returns a string representing the null device. On Mac OS, this is
199 "Dev:Null".
200 rootdir
202 Returns a string representing the root directory. Under MacPerl,
203 returns the name of the startup volume, since that's the closest in
204 concept, although other volumes aren't rooted there. The name has a
205 trailing ":", because that's the correct specification for a volume
206 name on Mac OS.
207 If Mac::Files could not be loaded, the empty string is returned.
209 tmpdir
211 Returns the contents of $ENV{TMPDIR}, if that directory exits or the
212 current working directory otherwise. Under MacPerl, $ENV{TMPDIR} will
213 contain a path like "MacintoshHD:Temporary Items:", which is a hidden
214 directory on your startup volume.
215 updir
217 Returns a string representing the parent directory. On Mac OS, this
218 is "::".
219 file_name_is_absolute
221 Takes as argument a path and returns true, if it is an absolute path.
222 If the path has a leading ":", it's a relative path. Otherwise, it's
223 an absolute path, unless the path doesn't contain any colons, i.e.
224 it's a name like "a". In this particular case, the path is considered
225 to be relative (i.e. it is considered to be a filename). Use ":" in
226 the appropriate place in the path if you want to distinguish
227 unambiguously. As a special case, the filename '' is always
228 considered to be absolute. Note that with version 1.2 of
229 File::Spec::Mac, this does no longer consult the local filesystem.
230 E.g.
232 File::Spec->file_name_is_absolute("a"); # false (relative)
234 File::Spec->file_name_is_absolute(":a:b:"); # false (relative)
235 File::Spec->file_name_is_absolute("MacintoshHD:"); # true (absolute)
236 File::Spec->file_name_is_absolute(""); # true (absolute)
237 path
239 Returns the null list for the MacPerl application, since the concept
240 is usually meaningless under Mac OS. But if you're using the MacPerl
241 tool under MPW, it gives back $ENV{Commands} suitably split, as is
242 done in :lib:ExtUtils:MM_Mac.pm.
243 splitpath
245 ($volume,$directories,$file) = File::Spec->splitpath( $path );
246 ($volume,$directories,$file) = File::Spec->splitpath( $path, $no_file );
247 Splits a path into volume, directory, and filename portions.
249 On Mac OS, assumes that the last part of the path is a filename
251 unless $no_file is true or a trailing separator ":" is present.
252 The volume portion is always returned with a trailing ":". The
254 directory portion is always returned with a leading (to denote a
255 relative path) and a trailing ":" (to denote a directory). The file
256 portion is always returned without a leading ":". Empty portions are
257 returned as empty string ''.
258 The results can be passed to "catpath()" to get back a path
260 equivalent to (usually identical to) the original path.
261 splitdir
263 The opposite of "catdir()".
264 @dirs = File::Spec->splitdir( $directories );
266 $directories should be only the directory portion of the path on
268 systems that have the concept of a volume or that have path syntax
269 that differentiates files from directories. Consider using
270 "splitpath()" otherwise.
271 Unlike just splitting the directories on the separator, empty
273 directory names ("") can be returned. Since "catdir()" on Mac OS
274 always appends a trailing colon to distinguish a directory path from
275 a file path, a single trailing colon will be ignored, i.e. there's no
276 empty directory name after it.
277 Hence, on Mac OS, both
279 File::Spec->splitdir( ":a:b::c:" ); and
281 File::Spec->splitdir( ":a:b::c" );
282 yield:
284 ( "a", "b", "::", "c")
286 while
288 File::Spec->splitdir( ":a:b::c::" );
290 yields:
292 ( "a", "b", "::", "c", "::")
294 catpath
296 $path = File::Spec->catpath($volume,$directory,$file);
297 Takes volume, directory and file portions and returns an entire path.
299 On Mac OS, $volume, $directory and $file are concatenated. A ':' is
300 inserted if need be. You may pass an empty string for each portion.
301 If all portions are empty, the empty string is returned. If $volume
302 is empty, the result will be a relative path, beginning with a ':'.
303 If $volume and $directory are empty, a leading ":" (if any) is
304 removed form $file and the remainder is returned. If $file is empty,
305 the resulting path will have a trailing ':'.
306 abs2rel
308 Takes a destination path and an optional base path and returns a
309 relative path from the base path to the destination path:
310 $rel_path = File::Spec->abs2rel( $path ) ;
312 $rel_path = File::Spec->abs2rel( $path, $base ) ;
313 Note that both paths are assumed to have a notation that
315 distinguishes a directory path (with trailing ':') from a file path
316 (without trailing ':').
317 If $base is not present or '', then the current working directory is
319 used. If $base is relative, then it is converted to absolute form
320 using "rel2abs()". This means that it is taken to be relative to the
321 current working directory.
322 If $path and $base appear to be on two different volumes, we will not
324 attempt to resolve the two paths, and we will instead simply return
325 $path. Note that previous versions of this module ignored the volume
326 of $base, which resulted in garbage results part of the time.
327 If $base doesn't have a trailing colon, the last element of $base is
329 assumed to be a filename. This filename is ignored. Otherwise all
330 path components are assumed to be directories.
331 If $path is relative, it is converted to absolute form using
333 "rel2abs()". This means that it is taken to be relative to the
334 current working directory.
335 Based on code written by Shigio Yamaguchi.
337 rel2abs
339 Converts a relative path to an absolute path:
340 $abs_path = File::Spec->rel2abs( $path ) ;
342 $abs_path = File::Spec->rel2abs( $path, $base ) ;
343 Note that both paths are assumed to have a notation that
345 distinguishes a directory path (with trailing ':') from a file path
346 (without trailing ':').
347 If $base is not present or '', then $base is set to the current
349 working directory. If $base is relative, then it is converted to
350 absolute form using "rel2abs()". This means that it is taken to be
351 relative to the current working directory.
352 If $base doesn't have a trailing colon, the last element of $base is
354 assumed to be a filename. This filename is ignored. Otherwise all
355 path components are assumed to be directories.
356 If $path is already absolute, it is returned and $base is ignored.
358 Based on code written by Shigio Yamaguchi.
360
362 See the authors list in File::Spec. Mac OS support by Paul Schinder
363 <schinder@pobox.com> and Thomas Wegner <wegner_thomas@yahoo.com>.
364
366 Copyright (c) 2004 by the Perl 5 Porters. All rights reserved.
367 This program is free software; you can redistribute it and/or modify it
369 under the same terms as Perl itself.
370
372 See File::Spec and File::Spec::Unix. This package overrides the
373 implementation of these methods, not the semantics.
374perl v5.10.1 2009-05-10 File::Spec::Mac(3pm)