Synopsis

 $ sudo apt-grip foo bar baz
 $ sudo apt-grip -M http://ftp.fr.debian.org/debian/ foo bar baz
 
 $ sudo apt-grip --clean-cache

Description

Emdebian Grip has a limited number of packages in the main repository, principally to reduce the size of the apt cache data. On occassion, individual packages from standard Debian need to be added to a single machine running Emdebian Grip. apt-grip has been written with that purpose in mind.

apt-grip requires DEB_VENDOR support in dpkg to determine how the package should be "gripped". The default Vendor is "emdebian-grip" but note the next section on the limitations of apt-grip if you plan to use it on an unmodified Debian system.

The usual case is that the system has already been upgraded to Emdebian Grip before apt-grip is used.

Contact the [email protected] mailing list for requests to add packages to Emdebian Grip repositories directly.

Downloading the Packages files can take a reasonable amount of time, so to grip a number of packages, either specify all packages in one command or use the "--keep-cache" option for each run and use the "--clean-cache" option at the end.

If the device running Grip has insufficient space to download and process the package(s), run apt-grip on a different machine of the using the "--build-only" and "--arch" options.

The processed archives will be in /var/lib/apt-grip/output/ and can be copied from there onto the device directly or by including the packages into a locally accessible repository. Once installed on the Grip device use "apt-grip -c" on the build machine to clear the cache. "--keep-cache" is implied when "--build-only" is set.

Note also that, in common with the rest of Emdebian processing, Install-Recommends is always turned off, so if you need a package that is only recommended by packages in the list given to "apt-grip", that package will need to be added to the list explicitly.

Limitations

Installing any package from repositories outside the normal apt sources (especially if those packages are subsequently modified as in emgrip) will list those packages as ``local or obsolete'' in package managers. Converted packages cannot be upgraded without repeating the call to "apt-grip" because "apt-get" does not know about the temporary mirror that "apt-grip" used to download the packages. This can cause problems if dependencies of such packages need to be upgraded. It is possible that the main system "apt" will try to remove these local packages in order to proceed with the main system upgrade.

The best option is to seek addition of such packages to the repository you use for your main apt sources. (Use the emdebian-grip-server package to create your own repository.)

"Gripping" a package means making a new version (with the em1 version suffix) with less files in the new package. See emgrip (1) for detailed information on that process. Changing the version string means that some dependencies need to be changed - particularly strict dependencies. This means that apt-grip could fail with some combinations of packages.

"apt-grip" uses the "--reinstall" option to apt-get to cope with some of these situations.

Strict dependency issues

If a source package builds multiple binary packages, where at least one package has a strict dependency on one of the other binary packages and one of those binary packages is already installed from Debian, it will be necessary to install Grip versions of both the binary packages involved so that the strict dependency can be satisfied.

 Source: foo
 Package: foo
 Depends: bar (= 0.0.1)
 Package: bar
 $ sudo apt-grip foo bar

In the example above, foo_0.0.1_amd64.deb will become foo_0.0.1em1_amd64.deb and will be given a strict dependency on "bar (= 0.0.1em1)" by emgrip.

Default mirror

apt-grip uses "http://ftp.uk.debian.org/debian/" as the default Debian mirror. Use the -M|--mirrror option to change it.

SecureApt

Use the "--no-auth" option to allow the use of unauthenticated repositories. Note that this disables authentication against all available repositories.

Upgrading to Grip

Change your sources list from debian mirrors to the emdebian grip mirror.

e.g. for unstable:

 deb http://www.emdebian.org/grip/ unstable main

(Emdebian Grip only supports Debian suites: unstable, sid, testing, squeeze, stable, lenny, lenny-proposed-updates.)

Then update and upgrade:

 $ sudo apt-get update
 $ sudo apt-get clean
 $ sudo apt-get upgrade
 $ sudo apt-get dist-upgrade

(Note that apt-get will usually report the ability to free several hundred megabytes on your system when some of your Debian packages are upgraded to Emdebian Grip but you still need enough room to actually download and unpack the new packages.) Use "apt-get clean" after the upgrade to recover more free space.

Grip components

Grip divides the archive further by creating new areas of the archive for packages related to development, debugging, documentation or java, again to reduce the final size of the cached package data on the system. If you want to use "apt-grip" on your Emdebian Grip system, ensure that you add the dev component to your apt sources:

 deb http://www.emdebian.org/grip/ unstable main dev

Similarly for doc, debug and java. Other components may be added from time to time, so check the Emdebian website:

 http://www.emdebian.org/grip/search.php

Add more components as required:

 deb http://www.emdebian.org/grip/ unstable main dev debug java

Emdebian Baked

apt-grip has been extended to help generate packages for use with Emdebian Baked. This has meant adding foreign architecture support as well as support for ignoring the status of currently installed packages on the device running apt-grip.

The difficult part of this process is managing updated packages and changed dependencies. apt-grip can only help with Debian stable.

emdebian-grip has not been backported to Lenny, so your development machine must be running Debian Squeeze or Sid (testing or unstable) to develop a Baked root filesystem based on Lenny.

Example apt-grip command for Baked

 $ sudo apt-grip -a mipsel -V emdebian-baked -S stable dash snmpd

Baked packages will then exist in /var/lib/apt-grip/output/, including all dependencies of the specified packages. These can then be included into an existing reprepro repository:

 $ reprepro includedeb stable /var/lib/apt-grip/output/*.deb

If your repository is to support more than one architecture, ensure that you remove or ignore the Architecture: all packages which have already been processed by apt-grip:

 $ sudo rm /var/lib/apt-grip/output*_all.deb

Then use the -A option to reprepro to only include the added architecture:

 $ reprepro -A armel includedeb stable /var/lib/apt-grip/output/*_armel.deb

For more information, see the emdebian website: http://www.emdebian.org/baked/