emgrip(1) converts a .deb to Emdebian Grip on-the-fly


 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


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 <[email protected]>
 Copyright (C) 2000-2002  Colin Watson <[email protected]>
 Copyright (C) 2002-2004  David Schleef <[email protected]>
 Copyright (C) 2004  Nikita Youshchenko <[email protected]>
 Copyright (C) 2004  Raphael Bossek <[email protected]>
 Copyright (C) 2007-2011  Neil Williams <[email protected]>
 Copyright (C) 2005 Joey Hess <[email protected]>
 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
 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
 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.


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'].


If none of these options are set, emgrip does nothing.


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.


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.


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.


Remove all files from /usr/share/lintian/overrides and /usr/share/linda/overrides - saves up to 1Mb.


Combination flag that sets all DEB_BUILD_OPTIONS for Emdebian Grip - noessential, nohelp, nodocs, nolintian


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.


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.


Remove any file that is found to be a perl script text executable by 'file' - used by Crush.


Combination flag that adds nosymbols and noperl to usegrip.


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".


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:


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).


Relatively simple, but a few checks are needed in case your list of possible packages includes packages already processed by dpkg-cross.

 set -e
 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"
    DEB_BUILD_OPTIONS="nodocs nohelp usegrip" ./emgrip -o $DIR $deb

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.