Provided by: stow_1.3.3-3.2_all bug

NAME

       stow - software package installation manager

SYNOPSIS

       stow [options] package...

DESCRIPTION

       This  manual  page  describes  GNU  Stow 1.3.3, 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 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. Since no actual operations are performed, stow -n  could  report  conflicts
              when  none would actually take place (see ``Conflicts'' in the info manual); but it
              won't fail to report conflicts that would take place.

       -c

       --conflicts
              Do not exit immediately when a conflict is encountered. This option  implies  `-n',
              and  is  used  to  search  for  all  conflicts that might arise from an actual Stow
              operation.  As  with  `-n',  however,  false  conflicts  might  be  reported   (see
              ``Conflicts'' in the info manual).

       -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, and 3; 0 is the default.  Using `-v' or `--verbose' increases
              the verbosity by one; using `--verbose=N' sets it to N.

       -D

       --delete
              Delete packages 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.

       -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
       ``Conflicts'' 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 info manual ``Stow 1.3.3: Managing the installation  of  software  packages''  by  Bob
       Glickstein, Zanshin Software, Inc.

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:

              1.  if no other package has a BAR subdirectory, everything's fine.

              2.  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 constructed by Charles Briscoe-Smith from parts of Stow's info manual.
       That manual contained the following notice, which, as it  says,  applied  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.

              Software and documentation Copyright (C) 1993, 1994, 1995, 1996 by  Bob  Glickstein
              <bobg+stow@zanshin.com>.

              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.

                                          28 March 1998                                   STOW(8)