Provided by: emdebian-grip_3.1.0_all 
NAME
emgrip - converts a .deb to Emdebian Grip on-the-fly
Synopsis
DEB_BUILD_OPTIONS='usegrip' emgrip [-v|--verbose] [-q|--quiet]
[--vendor VENDOR] [-o|--outdir DIRECTORY] FILENAME
where FILENAME is a .dsc, a .changes or a .deb
emgrip -?|-h|--help|--version
Description
Converts a .deb package to Emdebian Grip by unpacking, pruning particular classes of files
(determined by DEB_BUILD_OPTIONS or the dpkg vendor support) and repacking with a
shortened description and the em1 version suffix.
For the Debian buildd, the unstable-grip vendor omits generation of Emdebian TDebs and
changes the suite name to use the -grip suffix.
When creating a public Emdebian Grip repository, it is strongly recommended to specify
.changes or .dsc files to allow the generation of Emdebian TDebs from the source package
as well as including the source package itself in the repository.
In .dsc mode, "emgrip" only processes the source package, as of version 3.0.0
If a file exists with the same name in the output directory, it will be overwritten.
Copyright and Licence
Copyright (C) 1997-2000 Roman Hodek <roman@hodek.net>
Copyright (C) 2000-2002 Colin Watson <cjwatson@debian.org>
Copyright (C) 2002-2004 David Schleef <ds@schleef.org>
Copyright (C) 2004 Nikita Youshchenko <yoush@cs.msu.su>
Copyright (C) 2004 Raphael Bossek <bossekr@debian.org>
Copyright (C) 2007-2011 Neil Williams <codehelp@debian.org>
Copyright (C) 2005 Joey Hess <joeyh@debian.org>
This package is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Emdebian Grip
The idea here is based on dpkg-cross:
1. receive .deb or .changes as a command-line option
2. parse DEB_BUILD_OPTIONS
3. unpack the .deb as dpkg-cross does
4. remove files as per DEB_BUILD_OPTIONS
5. repack the .deb with an Emdebian version suffix.
6. build new .deb and revise .changes so that the
original source can be retained.
7. Include the gripped packages into a local mirror
to reduce the size of Packages.gz and the size of
the mirror itself.
As few dependencies as possible - this script should become a new package and have a new
set of lintian checks to allow perl etc.
NO FUNCTIONAL CHANGES IN THE FINAL .DEB !
Conversion of Debian translations to Emdebian TDebs (where supported by the build options)
needs to be done inside the source package so a .changes file is needed for this step. If
the .changes file references a Debian TDeb, emgrip will run 'em_installtdeb --no-sign'
inside the source package.
Individual packages containing translation files will have the translation files removed
and Debian TDebs are skipped.
Future versions may also understand Dpkg Classes but until those are implemented, this
uses brute force.
Set the build options by placing a file in /etc/dpkg/origins/ containing the build options
in a field called "Grip-Build-Option" and call "emgrip" with the "--vendor" option or
"DEB_VENDOR" environment variable.
dpkg-vendor fields used by emgrip with default values:
Vendor: emdebian-grip
Vendor-Name: Emdebian Grip
Grip-Build-Option: usegrip
Short-Desc-Suffix: gripped
The "Short-Desc-Suffix" is wrapped in parentheses and appended to the short description
[default is 'gripped'].
DEB_BUILD_OPTIONS
If none of these options are set, emgrip does nothing.
nodocs
Remove all content in /usr/share/doc/*/ except the copyright file and compress the
copyright file itself. Remove manpages and info pages (translated or not). Also remove
doc-base files that describe the documentation that no longer exists.
nohelp
Remove even help files from all packages, including -doc packages. Includes removing
/usr/share/gtk-doc/html and /usr/share/gnome/help/\$package Despite removing the help
files, dependencies on help file utilities like scrollkeeper will remain, at least for
Lenny.
noessential
Remove the 'Essential: yes' tag from DEBIAN/control - this is a brute force removal, no
additional dependencies are to be generated (no patches) so care is needed here.
nolintian
Remove all files from /usr/share/lintian/overrides and /usr/share/linda/overrides - saves
up to 1Mb.
usegrip
Combination flag that sets all DEB_BUILD_OPTIONS for Emdebian Grip - noessential, nohelp,
nodocs, nolintian
debiangrip
Debian-only flag which omits processing of TDebs, even for .changes files then changes the
distribution to match the Emdebian suites in Debian. Other processing remains the same as
the usegrip option.
nosymbols
Currently being tested - the idea is to drop DEBIAN/symbols files but this could have
unpredictable effects on packages built on a system lacking these symbols. The space saved
by dropping these files might not be worth the cost, so 'usegrip' does not yet activate
'nosymbols'. This might be suitable for Crush, maybe not Grip.
noperl
Remove any file that is found to be a perl script text executable by 'file' - used by
Crush.
usecrush
Combination flag that adds nosymbols and noperl to usegrip.
noscripts
Drop all maintainer scripts from all packages irrespective of the type of script. Includes
removing debconf templates and config scripts. md5sums files and triggers are also
removed. Scripts are moved to a scripts/ subdirectory of the output directory used by
"emgrip".
usebaked
Combination flag that adds noscripts and nosymbols to usegrip. Add "noperl" to use Baked
for Crush.
Field removal
Functional control fields are retained but the question arises:
Who defines functional?
Well, for the current purposes of Emdebian Grip, functional includes only the following
control fields:
Package
Source
Version
Architecture
Maintainer
Installed-Size
Depends
Pre-Depends
Multi-Arch
Conflicts
Replaces
Section
Priority
Description
Task
XS-Python-Version
Recommends is explicitly rejected, as is Suggests - the expectation is that Emdebian Grip
will disable Install-Recommends in apt anyway, so that Gripped packages can be mixed with
Debian or locally-built packages.
Note also that 'Essential' is not preserved.
Homepage, VCS* and all X- control fields are dropped.
The net result is a (potentially) much cleaner dpkg database.
The description is trimmed to four lines (or three if the fourth line is empty).
Automation
Relatively simple, but a few checks are needed in case your list of possible packages
includes packages already processed by dpkg-cross.
#!/bin/sh
set -e
DIR=/tmp/myrepo/
for deb in `ls /var/cache/apt/archives/*.deb`; do
cross=`echo $deb | grep "\-.*-cross" || true`
if [ ! -z "$cross" ]; then
echo "skipping dpkg-cross package: $deb"
continue
fi
DEB_BUILD_OPTIONS="nodocs nohelp usegrip" ./emgrip -o $DIR $deb
done
With "dpkg-vendor" support, DEB_BUILD_OPTIONS can be replaced by setting the vendor.
A similar script should be able to cope with obtaining .changes files to retain the source
packages.
Despite using dcut internally, emgrip isn't set up to obtain the .changes files directly
from http://incoming.debian.org, a wrapper script would be needed.
An additional wrapper is likely to be needed to allow an Emdebian Grip repository to
"catch-up" with the existing Debian mirrors, e.g. if the first upload to the Grip
repository is a binary-only upload without a referenced .orig.tar.gz.
emgrip does ensure that the .tar.gz is copied into the output directory and reprepro can
locate the relevant files if the --ignore=missingfile option is passed. Sadly, this
functionality is not preserved in the reprepro processincoming mode.
To ease the process of gripping an existing mirror, the emdebian-grip-server package
depends on 'reprepro' to create a filtered Debian mirror that can be kept up to date,
generates meta-data for Emdebian Grip, builds gripped packages in an 'incoming/' directory
and includes the packages into the final Emdebian Grip repository.
Once a package has been "gripped", the binary packages could be removed from the filtered
mirror - the source packages (particularly the .orig.tar.gz) are probably best retained in
the filtered mirror.