1IO::FILE=IO(0X81D9F0)(1U)ser Contributed Perl DocumentatiIoOn::FILE=IO(0X81D9F0)(1)
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6 stow - software package installation manager
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9 stow [ options ] package ...
10
12 This manual page describes GNU Stow 2.2.2, a program for managing the
13 installation of software packages. This is not the definitive
14 documentation for stow; for that, see the info manual.
15 Stow is a tool for managing the installation of multiple software
17 packages in the same run-time directory tree. One historical difficulty
18 of this task has been the need to administer, upgrade, install, and
19 remove files in independent packages without confusing them with other
20 files sharing the same filesystem space. For instance, it is common to
21 install Perl and Emacs in /usr/local. When one does so, one winds up
22 (as of Perl 4.036 and Emacs 19.22) with the following files in
23 /usr/local/man/man1: a2p.1; ctags.1; emacs.1; etags.1; h2ph.1; perl.1;
24 and s2p.1. Now suppose it's time to uninstall Perl. Which man pages
25 get removed? Obviously perl.1 is one of them, but it should not be the
26 administrator's responsibility to memorize the ownership of individual
27 files by separate packages.
28 The approach used by Stow is to install each package into its own tree,
30 then use symbolic links to make it appear as though the files are
31 installed in the common tree. Administration can be performed in the
32 package's private tree in isolation from clutter from other packages.
33 Stow can then be used to update the symbolic links. The structure of
34 each private tree should reflect the desired structure in the common
35 tree; i.e. (in the typical case) there should be a bin directory
36 containing executables, a man/man1 directory containing section 1 man
37 pages, and so on.
38 Stow was inspired by Carnegie Mellon's Depot program, but is
40 substantially simpler and safer. Whereas Depot required database files
41 to keep things in sync, Stow stores no extra state between runs, so
42 there's no danger (as there was in Depot) of mangling directories when
43 file hierarchies don't match the database. Also unlike Depot, Stow will
44 never delete any files, directories, or links that appear in a Stow
45 directory (e.g., /usr/local/stow/emacs), so it's always possible to
46 rebuild the target tree (e.g., /usr/local).
47
49 A "package" is a related collection of files and directories that you
50 wish to administer as a unit -- e.g., Perl or Emacs -- and that needs
51 to be installed in a particular directory structure -- e.g., with bin,
52 lib, and man subdirectories.
53 A "target directory" is the root of a tree in which one or more
55 packages wish to appear to be installed. A common, but by no means the
56 only such location is /usr/local. The examples in this manual page
57 will use /usr/local as the target directory.
58 A "stow directory" is the root of a tree containing separate packages
60 in private subtrees. When Stow runs, it uses the current directory as
61 the default stow directory. The examples in this manual page will use
62 /usr/local/stow as the stow directory, so that individual packages will
63 be, for example, /usr/local/stow/perl and /usr/local/stow/emacs.
64 An "installation image" is the layout of files and directories required
66 by a package, relative to the target directory. Thus, the installation
67 image for Perl includes: a bin directory containing perl and a2p (among
68 others); an info directory containing Texinfo documentation; a lib/perl
69 directory containing Perl libraries; and a man/man1 directory
70 containing man pages.
71 A "package directory" is the root of a tree containing the installation
73 image for a particular package. Each package directory must reside in a
74 stow directory -- e.g., the package directory /usr/local/stow/perl must
75 reside in the stow directory /usr/local/stow. The "name" of a package
76 is the name of its directory within the stow directory -- e.g., perl.
77 Thus, the Perl executable might reside in
79 /usr/local/stow/perl/bin/perl, where /usr/local is the target
80 directory, /usr/local/stow is the stow directory, /usr/local/stow/perl
81 is the package directory, and bin/perl within is part of the
82 installation image.
83 A "symlink" is a symbolic link. A symlink can be "relative" or
85 "absolute". An absolute symlink names a full path; that is, one
86 starting from /. A relative symlink names a relative path; that is,
87 one not starting from /. The target of a relative symlink is computed
88 starting from the symlink's own directory. Stow only creates relative
89 symlinks.
90
92 The stow directory is assumed to be the value of the "STOW_DIR"
93 environment variable or if unset the current directory, and the target
94 directory is assumed to be the parent of the current directory (so it
95 is typical to execute stow from the directory /usr/local/stow). Each
96 package given on the command line is the name of a package in the stow
97 directory (e.g., perl). By default, they are installed into the target
98 directory (but they can be deleted instead using "-D").
99 -n
101 --no
102 Do not perform any operations that modify the filesystem; merely
103 show what would happen.
104 -d DIR
106 --dir=DIR
107 Set the stow directory to "DIR" instead of the current directory.
108 This also has the effect of making the default target directory be
109 the parent of "DIR".
110 -t DIR
112 --target=DIR
113 Set the target directory to "DIR" instead of the parent of the stow
114 directory.
115 -v
117 --verbose[=N]
118 Send verbose output to standard error describing what Stow is
119 doing. Verbosity levels are 0, 1, 2, 3, and 4; 0 is the default.
120 Using "-v" or "--verbose" increases the verbosity by one; using
121 `--verbose=N' sets it to N.
122 -S
124 --stow
125 Stow the packages that follow this option into the target
126 directory. This is the default action and so can be omitted if you
127 are only stowing packages rather than performing a mixture of
128 stow/delete/restow actions.
129 -D
131 --delete
132 Unstow the packages that follow this option from the target
133 directory rather than installing them.
134 -R
136 --restow
137 Restow packages (first unstow, then stow again). This is useful for
138 pruning obsolete symlinks from the target tree after updating the
139 software in a package.
140 --adopt
142 Warning! This behaviour is specifically intended to alter the
143 contents of your stow directory. If you do not want that, this
144 option is not for you.
145 When stowing, if a target is encountered which already exists but
147 is a plain file (and hence not owned by any existing stow package),
148 then normally Stow will register this as a conflict and refuse to
149 proceed. This option changes that behaviour so that the file is
150 moved to the same relative place within the package's installation
151 image within the stow directory, and then stowing proceeds as
152 before. So effectively, the file becomes adopted by the stow
153 package, without its contents changing.
154 --no-folding
156 Disable folding of newly stowed directories when stowing, and
157 refolding of newly foldable directories when unstowing.
158 --ignore=REGEX
160 Ignore files ending in this Perl regex.
161 --defer=REGEX
163 Don't stow files beginning with this Perl regex if the file is
164 already stowed to another package.
165 --override=REGEX
167 Force stowing files beginning with this Perl regex if the file is
168 already stowed to another package.
169 -V
171 --version
172 Show Stow version number, and exit.
173 -h
175 --help
176 Show Stow command syntax, and exit.
177
179 The default action of Stow is to install a package. This means creating
180 symlinks in the target tree that point into the package tree. Stow
181 attempts to do this with as few symlinks as possible; in other words,
182 if Stow can create a single symlink that points to an entire subtree
183 within the package tree, it will choose to do that rather than create a
184 directory in the target tree and populate it with symlinks.
185 For example, suppose that no packages have yet been installed in
187 /usr/local; it's completely empty (except for the stow subdirectory, of
188 course). Now suppose the Perl package is installed. Recall that it
189 includes the following directories in its installation image: bin;
190 info; lib/perl; man/man1. Rather than creating the directory
191 /usr/local/bin and populating it with symlinks to ../stow/perl/bin/perl
192 and ../stow/perl/bin/a2p (and so on), Stow will create a single
193 symlink, /usr/local/bin, which points to stow/perl/bin. In this way,
194 it still works to refer to /usr/local/bin/perl and /usr/local/bin/a2p,
195 and fewer symlinks have been created. This is called "tree folding",
196 since an entire subtree is "folded" into a single symlink.
197 To complete this example, Stow will also create the symlink
199 /usr/local/info pointing to stow/perl/info; the symlink /usr/local/lib
200 pointing to stow/perl/lib; and the symlink /usr/local/man pointing to
201 stow/perl/man.
202 Now suppose that instead of installing the Perl package into an empty
204 target tree, the target tree is not empty to begin with. Instead, it
205 contains several files and directories installed under a different
206 system-administration philosophy. In particular, /usr/local/bin already
207 exists and is a directory, as are /usr/local/lib and
208 /usr/local/man/man1. In this case, Stow will descend into
209 /usr/local/bin and create symlinks to ../stow/perl/bin/perl and
210 ../stow/perl/bin/a2p (etc.), and it will descend into /usr/local/lib
211 and create the tree-folding symlink perl pointing to
212 ../stow/perl/lib/perl, and so on. As a rule, Stow only descends as far
213 as necessary into the target tree when it can create a tree-folding
214 symlink.
215 The time often comes when a tree-folding symlink has to be undone
217 because another package uses one or more of the folded subdirectories
218 in its installation image. This operation is called "splitting open" a
219 folded tree. It involves removing the original symlink from the target
220 tree, creating a true directory in its place, and then populating the
221 new directory with symlinks to the newly-installed package and to the
222 old package that used the old symlink. For example, suppose that after
223 installing Perl into an empty /usr/local, we wish to install Emacs.
224 Emacs's installation image includes a bin directory containing the
225 emacs and etags executables, among others. Stow must make these files
226 appear to be installed in /usr/local/bin, but presently /usr/local/bin
227 is a symlink to stow/perl/bin. Stow therefore takes the following
228 steps: the symlink /usr/local/bin is deleted; the directory
229 /usr/local/bin is created; links are made from /usr/local/bin to
230 ../stow/emacs/bin/emacs and ../stow/emacs/bin/etags; and links are made
231 from /usr/local/bin to ../stow/perl/bin/perl and ../stow/perl/bin/a2p.
232 When splitting open a folded tree, Stow makes sure that the symlink it
234 is about to remove points inside a valid package in the current stow
235 directory.
236 Stow will never delete anything that it doesn't own.
238 Stow "owns" everything living in the target tree that points into a
239 package in the stow directory. Anything Stow owns, it can recompute if
240 lost. Note that by this definition, Stow doesn't "own" anything in the
241 stow directory or in any of the packages.
242 If Stow needs to create a directory or a symlink in the target tree and
244 it cannot because that name is already in use and is not owned by Stow,
245 then a conflict has arisen. See the "Conflicts" section in the info
246 manual.
247
249 When the "-D" option is given, the action of Stow is to delete a
250 package from the target tree. Note that Stow will not delete anything
251 it doesn't "own". Deleting a package does not mean removing it from the
252 stow directory or discarding the package tree.
253 To delete a package, Stow recursively scans the target tree, skipping
255 over the stow directory (since that is usually a subdirectory of the
256 target tree) and any other stow directories it encounters (see
257 "Multiple stow directories" in the info manual). Any symlink it finds
258 that points into the package being deleted is removed. Any directory
259 that contained only symlinks to the package being deleted is removed.
260 Any directory that, after removing symlinks and empty subdirectories,
261 contains only symlinks to a single other package, is considered to be a
262 previously "folded" tree that was "split open." Stow will re-fold the
263 tree by removing the symlinks to the surviving package, removing the
264 directory, then linking the directory back to the surviving package.
265
267 The full documentation for stow is maintained as a Texinfo manual. If
268 the info and stow programs are properly installed at your site, the
269 command
270 info stow
272 should give you access to the complete manual.
274
276 Please report bugs in Stow using the Debian bug tracking system.
277 Currently known bugs include:
279 · The empty-directory problem.
281 If package foo includes an empty directory -- say, foo/bar -- then
283 if no other package has a bar subdirectory, everything's fine. If
284 another stowed package quux, has a bar subdirectory, then when
285 stowing, targetdir/bar will be "split open" and the contents of
286 quux/bar will be individually stowed. So far, so good. But when
287 unstowing quux, targetdir/bar will be removed, even though foo/bar
288 needs it to remain. A workaround for this problem is to create a
289 file in foo/bar as a placeholder. If you name that file
290 .placeholder, it will be easy to find and remove such files when
291 this bug is fixed.
292 · When using multiple stow directories (see "Multiple stow
294 directories" in the info manual), Stow fails to "split open" tree-
295 folding symlinks (see "Installing packages" in the info manual)
296 that point into a stow directory which is not the one in use by the
297 current Stow command. Before failing, it should search the target
298 of the link to see whether any element of the path contains a .stow
299 file. If it finds one, it can "learn" about the cooperating stow
300 directory to short-circuit the .stow search the next time it
301 encounters a tree-folding symlink.
302
304 This man page was originally constructed by Charles Briscoe-Smith from
305 parts of Stow's info manual, and then converted to POD format by Adam
306 Spiers. The info manual contains the following notice, which, as it
307 says, applies to this manual page, too. The text of the section
308 entitled "GNU General Public License" can be found in the file
309 /usr/share/common-licenses/GPL on any Debian GNU/Linux system. If you
310 don't have access to a Debian system, or the GPL is not there, write to
311 the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
312 MA, 02111-1307, USA.
313
315 Copyright (C) 1993, 1994, 1995, 1996 by Bob Glickstein
316 <bobg+stow@zanshin.com>; 2000, 2001 by Guillaume Morin; 2007 by Kahlil
317 Hodgson; 2011 by Adam Spiers; and others.
318 Permission is granted to make and distribute verbatim copies of this
320 manual provided the copyright notice and this permission notice are
321 preserved on all copies.
322 Permission is granted to copy and distribute modified versions of this
324 manual under the conditions for verbatim copying, provided also that
325 the section entitled "GNU General Public License" is included with the
326 modified manual, and provided that the entire resulting derived work is
327 distributed under the terms of a permission notice identical to this
328 one.
329 Permission is granted to copy and distribute translations of this
331 manual into another language, under the above conditions for modified
332 versions, except that this permission notice may be stated in a
333 translation approved by the Free Software Foundation.
334perl v5.20.1 2015-11-09 IO::FILE=IO(0X81D9F0)(1)