Provided by: stow_2.2.2-1_all 
NAME
stow - software package installation manager
SYNOPSIS
stow [ options ] package ...
DESCRIPTION
This manual page describes GNU Stow 2.2.2, a program for managing the installation of
software packages. This is not the definitive documentation for stow; for that, see the
info manual.
Stow is a tool for managing the installation of multiple software packages in the same
run-time directory tree. One historical difficulty of this task has been the need to
administer, upgrade, install, and remove files in independent packages without confusing
them with other files sharing the same filesystem space. For instance, it is common to
install Perl and Emacs in /usr/local. When one does so, one winds up (as of Perl 4.036
and Emacs 19.22) with the following files in /usr/local/man/man1: a2p.1; ctags.1; emacs.1;
etags.1; h2ph.1; perl.1; and s2p.1. Now suppose it's time to uninstall Perl. Which man
pages get removed? Obviously perl.1 is one of them, but it should not be the
administrator's responsibility to memorize the ownership of individual files by separate
packages.
The approach used by Stow is to install each package into its own tree, then use symbolic
links to make it appear as though the files are installed in the common tree.
Administration can be performed in the package's private tree in isolation from clutter
from other packages. Stow can then be used to update the symbolic links. The structure of
each private tree should reflect the desired structure in the common tree; i.e. (in the
typical case) there should be a bin directory containing executables, a man/man1 directory
containing section 1 man pages, and so on.
Stow was inspired by Carnegie Mellon's Depot program, but is substantially simpler and
safer. Whereas Depot required database files to keep things in sync, Stow stores no extra
state between runs, so there's no danger (as there was in Depot) of mangling directories
when file hierarchies don't match the database. Also unlike Depot, Stow will never delete
any files, directories, or links that appear in a Stow directory (e.g.,
/usr/local/stow/emacs), so it's always possible to rebuild the target tree (e.g.,
/usr/local).
TERMINOLOGY
A "package" is a related collection of files and directories that you wish to administer
as a unit -- e.g., Perl or Emacs -- and that needs to be installed in a particular
directory structure -- e.g., with bin, lib, and man subdirectories.
A "target directory" is the root of a tree in which one or more packages wish to appear to
be installed. A common, but by no means the only such location is /usr/local. The
examples in this manual page will use /usr/local as the target directory.
A "stow directory" is the root of a tree containing separate packages in private subtrees.
When Stow runs, it uses the current directory as the default stow directory. The examples
in this manual page will use /usr/local/stow as the stow directory, so that individual
packages will be, for example, /usr/local/stow/perl and /usr/local/stow/emacs.
An "installation image" is the layout of files and directories required by a package,
relative to the target directory. Thus, the installation image for Perl includes: a bin
directory containing perl and a2p (among others); an info directory containing Texinfo
documentation; a lib/perl directory containing Perl libraries; and a man/man1 directory
containing man pages.
A "package directory" is the root of a tree containing the installation image for a
particular package. Each package directory must reside in a stow directory -- e.g., the
package directory /usr/local/stow/perl must reside in the stow directory /usr/local/stow.
The "name" of a package is the name of its directory within the stow directory -- e.g.,
perl.
Thus, the Perl executable might reside in /usr/local/stow/perl/bin/perl, where /usr/local
is the target directory, /usr/local/stow is the stow directory, /usr/local/stow/perl is
the package directory, and bin/perl within is part of the installation image.
A "symlink" is a symbolic link. A symlink can be "relative" or "absolute". An absolute
symlink names a full path; that is, one starting from /. A relative symlink names a
relative path; that is, one not starting from /. The target of a relative symlink is
computed starting from the symlink's own directory. Stow only creates relative symlinks.
OPTIONS
The stow directory is assumed to be the value of the "STOW_DIR" environment variable or if
unset the current directory, and the target directory is assumed to be the parent of the
current directory (so it is typical to execute stow from the directory /usr/local/stow).
Each package given on the command line is the name of a package in the stow directory
(e.g., perl). By default, they are installed into the target directory (but they can be
deleted instead using "-D").
-n
--no
Do not perform any operations that modify the filesystem; merely show what would
happen.
-d DIR
--dir=DIR
Set the stow directory to "DIR" instead of the current directory. This also has the
effect of making the default target directory be the parent of "DIR".
-t DIR
--target=DIR
Set the target directory to "DIR" instead of the parent of the stow directory.
-v
--verbose[=N]
Send verbose output to standard error describing what Stow is doing. Verbosity levels
are 0, 1, 2, 3, and 4; 0 is the default. Using "-v" or "--verbose" increases the
verbosity by one; using `--verbose=N' sets it to N.
-S
--stow
Stow the packages that follow this option into the target directory. This is the
default action and so can be omitted if you are only stowing packages rather than
performing a mixture of stow/delete/restow actions.
-D
--delete
Unstow the packages that follow this option from the target directory rather than
installing them.
-R
--restow
Restow packages (first unstow, then stow again). This is useful for pruning obsolete
symlinks from the target tree after updating the software in a package.
--adopt
Warning! This behaviour is specifically intended to alter the contents of your stow
directory. If you do not want that, this option is not for you.
When stowing, if a target is encountered which already exists but is a plain file (and
hence not owned by any existing stow package), then normally Stow will register this
as a conflict and refuse to proceed. This option changes that behaviour so that the
file is moved to the same relative place within the package's installation image
within the stow directory, and then stowing proceeds as before. So effectively, the
file becomes adopted by the stow package, without its contents changing.
--no-folding
Disable folding of newly stowed directories when stowing, and refolding of newly
foldable directories when unstowing.
--ignore=REGEX
Ignore files ending in this Perl regex.
--defer=REGEX
Don't stow files beginning with this Perl regex if the file is already stowed to
another package.
--override=REGEX
Force stowing files beginning with this Perl regex if the file is already stowed to
another package.
-V
--version
Show Stow version number, and exit.
-h
--help
Show Stow command syntax, and exit.
INSTALLING PACKAGES
The default action of Stow is to install a package. This means creating symlinks in the
target tree that point into the package tree. Stow attempts to do this with as few
symlinks as possible; in other words, if Stow can create a single symlink that points to
an entire subtree within the package tree, it will choose to do that rather than create a
directory in the target tree and populate it with symlinks.
For example, suppose that no packages have yet been installed in /usr/local; it's
completely empty (except for the stow subdirectory, of course). Now suppose the Perl
package is installed. Recall that it includes the following directories in its
installation image: bin; info; lib/perl; man/man1. Rather than creating the directory
/usr/local/bin and populating it with symlinks to ../stow/perl/bin/perl and
../stow/perl/bin/a2p (and so on), Stow will create a single symlink, /usr/local/bin, which
points to stow/perl/bin. In this way, it still works to refer to /usr/local/bin/perl and
/usr/local/bin/a2p, and fewer symlinks have been created. This is called "tree folding",
since an entire subtree is "folded" into a single symlink.
To complete this example, Stow will also create the symlink /usr/local/info pointing to
stow/perl/info; the symlink /usr/local/lib pointing to stow/perl/lib; and the symlink
/usr/local/man pointing to stow/perl/man.
Now suppose that instead of installing the Perl package into an empty target tree, the
target tree is not empty to begin with. Instead, it contains several files and directories
installed under a different system-administration philosophy. In particular,
/usr/local/bin already exists and is a directory, as are /usr/local/lib and
/usr/local/man/man1. In this case, Stow will descend into /usr/local/bin and create
symlinks to ../stow/perl/bin/perl and ../stow/perl/bin/a2p (etc.), and it will descend
into /usr/local/lib and create the tree-folding symlink perl pointing to
../stow/perl/lib/perl, and so on. As a rule, Stow only descends as far as necessary into
the target tree when it can create a tree-folding symlink.
The time often comes when a tree-folding symlink has to be undone because another package
uses one or more of the folded subdirectories in its installation image. This operation is
called "splitting open" a folded tree. It involves removing the original symlink from the
target tree, creating a true directory in its place, and then populating the new directory
with symlinks to the newly-installed package and to the old package that used the old
symlink. For example, suppose that after installing Perl into an empty /usr/local, we wish
to install Emacs. Emacs's installation image includes a bin directory containing the
emacs and etags executables, among others. Stow must make these files appear to be
installed in /usr/local/bin, but presently /usr/local/bin is a symlink to stow/perl/bin.
Stow therefore takes the following steps: the symlink /usr/local/bin is deleted; the
directory /usr/local/bin is created; links are made from /usr/local/bin to
../stow/emacs/bin/emacs and ../stow/emacs/bin/etags; and links are made from
/usr/local/bin to ../stow/perl/bin/perl and ../stow/perl/bin/a2p.
When splitting open a folded tree, Stow makes sure that the symlink it is about to remove
points inside a valid package in the current stow directory.
Stow will never delete anything that it doesn't own.
Stow "owns" everything living in the target tree that points into a package in the stow
directory. Anything Stow owns, it can recompute if lost. Note that by this definition,
Stow doesn't "own" anything in the stow directory or in any of the packages.
If Stow needs to create a directory or a symlink in the target tree and it cannot because
that name is already in use and is not owned by Stow, then a conflict has arisen. See the
"Conflicts" section in the info manual.
DELETING PACKAGES
When the "-D" option is given, the action of Stow is to delete a package from the target
tree. Note that Stow will not delete anything it doesn't "own". Deleting a package does
not mean removing it from the stow directory or discarding the package tree.
To delete a package, Stow recursively scans the target tree, skipping over the stow
directory (since that is usually a subdirectory of the target tree) and any other stow
directories it encounters (see "Multiple stow directories" in the info manual). Any
symlink it finds that points into the package being deleted is removed. Any directory that
contained only symlinks to the package being deleted is removed. Any directory that, after
removing symlinks and empty subdirectories, contains only symlinks to a single other
package, is considered to be a previously "folded" tree that was "split open." Stow will
re-fold the tree by removing the symlinks to the surviving package, removing the
directory, then linking the directory back to the surviving package.
SEE ALSO
The full documentation for stow is maintained as a Texinfo manual. If the info and stow
programs are properly installed at your site, the command
info stow
should give you access to the complete manual.
BUGS
Please report bugs in Stow using the Debian bug tracking system.
Currently known bugs include:
• The empty-directory problem.
If package foo includes an empty directory -- say, foo/bar -- then if no other package
has a bar subdirectory, everything's fine. If another stowed package quux, has a bar
subdirectory, then when stowing, targetdir/bar will be "split open" and the contents
of quux/bar will be individually stowed. So far, so good. But when unstowing quux,
targetdir/bar will be removed, even though foo/bar needs it to remain. A workaround
for this problem is to create a file in foo/bar as a placeholder. If you name that
file .placeholder, it will be easy to find and remove such files when this bug is
fixed.
• When using multiple stow directories (see "Multiple stow directories" in the info
manual), Stow fails to "split open" tree-folding symlinks (see "Installing packages"
in the info manual) that point into a stow directory which is not the one in use by
the current Stow command. Before failing, it should search the target of the link to
see whether any element of the path contains a .stow file. If it finds one, it can
"learn" about the cooperating stow directory to short-circuit the .stow search the
next time it encounters a tree-folding symlink.
AUTHOR
This man page was originally constructed by Charles Briscoe-Smith from parts of Stow's
info manual, and then converted to POD format by Adam Spiers. The info manual contains
the following notice, which, as it says, applies to this manual page, too. The text of
the section entitled "GNU General Public License" can be found in the file
/usr/share/common-licenses/GPL-2 on any Debian GNU/Linux system. If you don't have access
to a Debian system, or the GPL is not there, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA, 02111-1307, USA.
COPYRIGHT
Copyright (C) 1993, 1994, 1995, 1996 by Bob Glickstein <bobg+stow@zanshin.com>; 2000, 2001
by Guillaume Morin; 2007 by Kahlil Hodgson; 2011 by Adam Spiers; and others.
Permission is granted to make and distribute verbatim copies of this manual provided the
copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the
conditions for verbatim copying, provided also that the section entitled "GNU General
Public License" is included with the modified manual, and provided that the entire
resulting derived work is distributed under the terms of a permission notice identical to
this one.
Permission is granted to copy and distribute translations of this manual into another
language, under the above conditions for modified versions, except that this permission
notice may be stated in a translation approved by the Free Software Foundation.