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<title>Ubuntu Policy Manual - Alternative versions of an interface - update-alternatives (from old Packaging Manual)</title>

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<link href="ch-scope.html" rel="chapter" title="1 About this manual">
<link href="ch-archive.html" rel="chapter" title="2 The Ubuntu Archive">
<link href="ch-binary.html" rel="chapter" title="3 Binary packages">
<link href="ch-source.html" rel="chapter" title="4 Source packages">
<link href="ch-controlfields.html" rel="chapter" title="5 Control files and their fields">
<link href="ch-maintainerscripts.html" rel="chapter" title="6 Package maintainer scripts and installation procedure">
<link href="ch-relationships.html" rel="chapter" title="7 Declaring relationships between packages">
<link href="ch-sharedlibs.html" rel="chapter" title="8 Shared libraries">
<link href="ch-opersys.html" rel="chapter" title="9 The Operating System">
<link href="ch-files.html" rel="chapter" title="10 Files">
<link href="ch-customized-programs.html" rel="chapter" title="11 Customized programs">
<link href="ch-docs.html" rel="chapter" title="12 Documentation">
<link href="ap-pkg-scope.html" rel="appendix" title="A Introduction and scope of these appendices">
<link href="ap-pkg-binarypkg.html" rel="appendix" title="B Binary packages (from old Packaging Manual)">
<link href="ap-pkg-sourcepkg.html" rel="appendix" title="C Source packages (from old Packaging Manual)">
<link href="ap-pkg-controlfields.html" rel="appendix" title="D Control files and their fields (from old Packaging Manual)">
<link href="ap-pkg-conffiles.html" rel="appendix" title="E Configuration file handling (from old Packaging Manual)">
<link href="ap-pkg-alternatives.html" rel="appendix" title="F Alternative versions of an interface - <code>update-alternatives</code> (from old Packaging Manual)">
<link href="ap-pkg-diversions.html" rel="appendix" title="G Diversions - overriding a package's version of a file (from old Packaging Manual)">
<link href="ch-scope.html#s1.1" rel="section" title="1.1 Scope">
<link href="ch-scope.html#s1.2" rel="section" title="1.2 New versions of this document">
<link href="ch-scope.html#s-authors" rel="section" title="1.3 Authors and Maintainers">
<link href="ch-scope.html#s-related" rel="section" title="1.4 Related documents">
<link href="ch-scope.html#s-definitions" rel="section" title="1.5 Definitions">
<link href="ch-archive.html#s-ulp" rel="section" title="2.1 The Ubuntu Licensing Policy">
<link href="ch-archive.html#s-sections" rel="section" title="2.2 Archive areas">
<link href="ch-archive.html#s-pkgcopyright" rel="section" title="2.3 Copyright considerations">
<link href="ch-archive.html#s-subsections" rel="section" title="2.4 Sections">
<link href="ch-archive.html#s-priorities" rel="section" title="2.5 Priorities">
<link href="ch-binary.html#s3.1" rel="section" title="3.1 The package name">
<link href="ch-binary.html#s-versions" rel="section" title="3.2 The version of a package">
<link href="ch-binary.html#s3.3" rel="section" title="3.3 The maintainer of a package">
<link href="ch-binary.html#s-descriptions" rel="section" title="3.4 The description of a package">
<link href="ch-binary.html#s3.5" rel="section" title="3.5 Dependencies">
<link href="ch-binary.html#s-virtual_pkg" rel="section" title="3.6 Virtual packages">
<link href="ch-binary.html#s3.7" rel="section" title="3.7 Base system">
<link href="ch-binary.html#s3.8" rel="section" title="3.8 Essential packages">
<link href="ch-binary.html#s-maintscripts" rel="section" title="3.9 Maintainer Scripts">
<link href="ch-source.html#s-standardsversion" rel="section" title="4.1 Standards conformance">
<link href="ch-source.html#s-pkg-relations" rel="section" title="4.2 Package relationships">
<link href="ch-source.html#s4.3" rel="section" title="4.3 Changes to the upstream sources">
<link href="ch-source.html#s-dpkgchangelog" rel="section" title="4.4 Ubuntu changelog: <code>debian/changelog</code>">
<link href="ch-source.html#s-dpkgcopyright" rel="section" title="4.5 Copyright: <code>debian/copyright</code>">
<link href="ch-source.html#s4.6" rel="section" title="4.6 Error trapping in makefiles">
<link href="ch-source.html#s-timestamps" rel="section" title="4.7 Time Stamps">
<link href="ch-source.html#s-restrictions" rel="section" title="4.8 Restrictions on objects in source packages">
<link href="ch-source.html#s-debianrules" rel="section" title="4.9 Main building script: <code>debian/rules</code>">
<link href="ch-source.html#s-substvars" rel="section" title="4.10 Variable substitutions: <code>debian/substvars</code>">
<link href="ch-source.html#s-debianwatch" rel="section" title="4.11 Optional upstream source location: <code>debian/watch</code>">
<link href="ch-source.html#s-debianfiles" rel="section" title="4.12 Generated files list: <code>debian/files</code>">
<link href="ch-source.html#s-embeddedfiles" rel="section" title="4.13 Convenience copies of code">
<link href="ch-source.html#s-readmesource" rel="section" title="4.14 Source package handling: <code>debian/README.source</code>">
<link href="ch-controlfields.html#s-controlsyntax" rel="section" title="5.1 Syntax of control files">
<link href="ch-controlfields.html#s-sourcecontrolfiles" rel="section" title="5.2 Source package control files -- <code>debian/control</code>">
<link href="ch-controlfields.html#s-binarycontrolfiles" rel="section" title="5.3 Binary package control files -- <code>DEBIAN/control</code>">
<link href="ch-controlfields.html#s-debiansourcecontrolfiles" rel="section" title="5.4 Debian source control files -- <samp>.dsc</samp>">
<link href="ch-controlfields.html#s-debianchangesfiles" rel="section" title="5.5 Debian changes files -- <code>.changes</code>">
<link href="ch-controlfields.html#s-controlfieldslist" rel="section" title="5.6 List of fields">
<link href="ch-controlfields.html#s5.7" rel="section" title="5.7 User-defined fields">
<link href="ch-maintainerscripts.html#s6.1" rel="section" title="6.1 Introduction to package maintainer scripts">
<link href="ch-maintainerscripts.html#s-idempotency" rel="section" title="6.2 Maintainer scripts idempotency">
<link href="ch-maintainerscripts.html#s-controllingterminal" rel="section" title="6.3 Controlling terminal for maintainer scripts">
<link href="ch-maintainerscripts.html#s-exitstatus" rel="section" title="6.4 Exit status">
<link href="ch-maintainerscripts.html#s-mscriptsinstact" rel="section" title="6.5 Summary of ways maintainer scripts are called">
<link href="ch-maintainerscripts.html#s-unpackphase" rel="section" title="6.6 Details of unpack phase of installation or upgrade">
<link href="ch-maintainerscripts.html#s-configdetails" rel="section" title="6.7 Details of configuration">
<link href="ch-maintainerscripts.html#s-removedetails" rel="section" title="6.8 Details of removal and/or configuration purging">
<link href="ch-relationships.html#s-depsyntax" rel="section" title="7.1 Syntax of relationship fields">
<link href="ch-relationships.html#s-binarydeps" rel="section" title="7.2 Binary Dependencies - <samp>Depends</samp>, <samp>Recommends</samp>, <samp>Suggests</samp>, <samp>Enhances</samp>, <samp>Pre-Depends</samp>">
<link href="ch-relationships.html#s-breaks" rel="section" title="7.3 Packages which break other packages - <samp>Breaks</samp>">
<link href="ch-relationships.html#s-conflicts" rel="section" title="7.4 Conflicting binary packages - <samp>Conflicts</samp>">
<link href="ch-relationships.html#s-virtual" rel="section" title="7.5 Virtual packages - <samp>Provides</samp>">
<link href="ch-relationships.html#s-replaces" rel="section" title="7.6 Overwriting files and replacing packages - <samp>Replaces</samp>">
<link href="ch-relationships.html#s-sourcebinarydeps" rel="section" title="7.7 Relationships between source and binary packages - <samp>Build-Depends</samp>, <samp>Build-Depends-Indep</samp>, <samp>Build-Conflicts</samp>, <samp>Build-Conflicts-Indep</samp>">
<link href="ch-sharedlibs.html#s-sharedlibs-runtime" rel="section" title="8.1 Run-time shared libraries">
<link href="ch-sharedlibs.html#s-sharedlibs-support-files" rel="section" title="8.2 Shared library support files">
<link href="ch-sharedlibs.html#s-sharedlibs-static" rel="section" title="8.3 Static libraries">
<link href="ch-sharedlibs.html#s-sharedlibs-dev" rel="section" title="8.4 Development files">
<link href="ch-sharedlibs.html#s-sharedlibs-intradeps" rel="section" title="8.5 Dependencies between the packages of the same library">
<link href="ch-sharedlibs.html#s-sharedlibs-shlibdeps" rel="section" title="8.6 Dependencies between the library and other packages - the <samp>shlibs</samp> system">
<link href="ch-opersys.html#s9.1" rel="section" title="9.1 File system hierarchy">
<link href="ch-opersys.html#s9.2" rel="section" title="9.2 Users and groups">
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<link href="ch-opersys.html#s9.4" rel="section" title="9.4 Console messages from <code>init.d</code> scripts">
<link href="ch-opersys.html#s9.5" rel="section" title="9.5 Cron jobs">
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<link href="ch-opersys.html#s-doc-base" rel="section" title="9.10 Registering Documents using doc-base">
<link href="ch-files.html#s10.1" rel="section" title="10.1 Binaries">
<link href="ch-files.html#s-libraries" rel="section" title="10.2 Libraries">
<link href="ch-files.html#s10.3" rel="section" title="10.3 Shared libraries">
<link href="ch-files.html#s-scripts" rel="section" title="10.4 Scripts">
<link href="ch-files.html#s10.5" rel="section" title="10.5 Symbolic links">
<link href="ch-files.html#s10.6" rel="section" title="10.6 Device files">
<link href="ch-files.html#s-config-files" rel="section" title="10.7 Configuration files">
<link href="ch-files.html#s10.8" rel="section" title="10.8 Log files">
<link href="ch-files.html#s10.9" rel="section" title="10.9 Permissions and owners">
<link href="ch-customized-programs.html#s-arch-spec" rel="section" title="11.1 Architecture specification strings">
<link href="ch-customized-programs.html#s11.2" rel="section" title="11.2 Daemons">
<link href="ch-customized-programs.html#s11.3" rel="section" title="11.3 Using pseudo-ttys and modifying wtmp, utmp and lastlog">
<link href="ch-customized-programs.html#s11.4" rel="section" title="11.4 Editors and pagers">
<link href="ch-customized-programs.html#s-web-appl" rel="section" title="11.5 Web servers and applications">
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<link href="ch-customized-programs.html#s11.7" rel="section" title="11.7 News system configuration">
<link href="ch-customized-programs.html#s11.8" rel="section" title="11.8 Programs for the X Window System">
<link href="ch-customized-programs.html#s-perl" rel="section" title="11.9 Perl programs and modules">
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<link href="ch-docs.html#s12.1" rel="section" title="12.1 Manual pages">
<link href="ch-docs.html#s12.2" rel="section" title="12.2 Info documents">
<link href="ch-docs.html#s12.3" rel="section" title="12.3 Additional documentation">
<link href="ch-docs.html#s12.4" rel="section" title="12.4 Preferred documentation formats">
<link href="ch-docs.html#s-copyrightfile" rel="section" title="12.5 Copyright information">
<link href="ch-docs.html#s12.6" rel="section" title="12.6 Examples">
<link href="ch-docs.html#s-changelogs" rel="section" title="12.7 Changelog files">
<link href="ap-pkg-binarypkg.html#s-pkg-bincreating" rel="section" title="B.1 Creating package files - <code>dpkg-deb</code>">
<link href="ap-pkg-binarypkg.html#s-pkg-controlarea" rel="section" title="B.2 Package control information files">
<link href="ap-pkg-binarypkg.html#s-pkg-controlfile" rel="section" title="B.3 The main control information file: <samp>control</samp>">
<link href="ap-pkg-binarypkg.html#sB.4" rel="section" title="B.4 Time Stamps">
<link href="ap-pkg-sourcepkg.html#s-pkg-sourcetools" rel="section" title="C.1 Tools for processing source packages">
<link href="ap-pkg-sourcepkg.html#s-pkg-sourcetree" rel="section" title="C.2 The Debianised source tree">
<link href="ap-pkg-sourcepkg.html#s-pkg-sourcearchives" rel="section" title="C.3 Source packages as archives">
<link href="ap-pkg-sourcepkg.html#sC.4" rel="section" title="C.4 Unpacking a Debian source package without <code>dpkg-source</code>">
<link href="ap-pkg-controlfields.html#sD.1" rel="section" title="D.1 Syntax of control files">
<link href="ap-pkg-controlfields.html#sD.2" rel="section" title="D.2 List of fields">
<link href="ap-pkg-conffiles.html#sE.1" rel="section" title="E.1 Automatic handling of configuration files by <code>dpkg</code>">
<link href="ap-pkg-conffiles.html#sE.2" rel="section" title="E.2 Fully-featured maintainer script configuration handling">
<link href="ch-archive.html#s-main" rel="subsection" title="2.2.1 The main archive area">
<link href="ch-archive.html#s-restricted" rel="subsection" title="2.2.2 The restricted archive area">
<link href="ch-archive.html#s-universe" rel="subsection" title="2.2.3 The universe archive area">
<link href="ch-archive.html#s-multiverse" rel="subsection" title="2.2.4 The multiverse archive area">
<link href="ch-binary.html#s3.2.1" rel="subsection" title="3.2.1 Version numbers based on dates">
<link href="ch-binary.html#s-synopsis" rel="subsection" title="3.4.1 The single line synopsis">
<link href="ch-binary.html#s-extendeddesc" rel="subsection" title="3.4.2 The extended description">
<link href="ch-binary.html#s-maintscriptprompt" rel="subsection" title="3.9.1 Prompting in maintainer scripts">
<link href="ch-source.html#s-debianrules-options" rel="subsection" title="4.9.1 <code>debian/rules</code> and <samp>DEB_BUILD_OPTIONS</samp>">
<link href="ch-controlfields.html#s-f-Source" rel="subsection" title="5.6.1 <samp>Source</samp>">
<link href="ch-controlfields.html#s-f-Maintainer" rel="subsection" title="5.6.2 <samp>Maintainer</samp>">
<link href="ch-controlfields.html#s-f-Uploaders" rel="subsection" title="5.6.3 <samp>Uploaders</samp>">
<link href="ch-controlfields.html#s-f-Changed-By" rel="subsection" title="5.6.4 <samp>Changed-By</samp>">
<link href="ch-controlfields.html#s-f-Section" rel="subsection" title="5.6.5 <samp>Section</samp>">
<link href="ch-controlfields.html#s-f-Priority" rel="subsection" title="5.6.6 <samp>Priority</samp>">
<link href="ch-controlfields.html#s-f-Package" rel="subsection" title="5.6.7 <samp>Package</samp>">
<link href="ch-controlfields.html#s-f-Architecture" rel="subsection" title="5.6.8 <samp>Architecture</samp>">
<link href="ch-controlfields.html#s-f-Essential" rel="subsection" title="5.6.9 <samp>Essential</samp>">
<link href="ch-controlfields.html#s5.6.10" rel="subsection" title="5.6.10 Package interrelationship fields: <samp>Depends</samp>, <samp>Pre-Depends</samp>, <samp>Recommends</samp>, <samp>Suggests</samp>, <samp>Breaks</samp>, <samp>Conflicts</samp>, <samp>Provides</samp>, <samp>Replaces</samp>, <samp>Enhances</samp>">
<link href="ch-controlfields.html#s-f-Standards-Version" rel="subsection" title="5.6.11 <samp>Standards-Version</samp>">
<link href="ch-controlfields.html#s-f-Version" rel="subsection" title="5.6.12 <samp>Version</samp>">
<link href="ch-controlfields.html#s-f-Description" rel="subsection" title="5.6.13 <samp>Description</samp>">
<link href="ch-controlfields.html#s-f-Distribution" rel="subsection" title="5.6.14 <samp>Distribution</samp>">
<link href="ch-controlfields.html#s-f-Date" rel="subsection" title="5.6.15 <samp>Date</samp>">
<link href="ch-controlfields.html#s-f-Format" rel="subsection" title="5.6.16 <samp>Format</samp>">
<link href="ch-controlfields.html#s-f-Urgency" rel="subsection" title="5.6.17 <samp>Urgency</samp>">
<link href="ch-controlfields.html#s-f-Changes" rel="subsection" title="5.6.18 <samp>Changes</samp>">
<link href="ch-controlfields.html#s-f-Binary" rel="subsection" title="5.6.19 <samp>Binary</samp>">
<link href="ch-controlfields.html#s-f-Installed-Size" rel="subsection" title="5.6.20 <samp>Installed-Size</samp>">
<link href="ch-controlfields.html#s-f-Files" rel="subsection" title="5.6.21 <samp>Files</samp>">
<link href="ch-controlfields.html#s-f-Closes" rel="subsection" title="5.6.22 <samp>Closes</samp>">
<link href="ch-controlfields.html#s-f-Launchpad-Bugs-Fixed" rel="subsection" title="5.6.23 <samp>Launchpad-Bugs-Fixed</samp>">
<link href="ch-controlfields.html#s-f-Homepage" rel="subsection" title="5.6.24 <samp>Homepage</samp>">
<link href="ch-relationships.html#s7.6.1" rel="subsection" title="7.6.1 Overwriting files in other packages">
<link href="ch-relationships.html#s7.6.2" rel="subsection" title="7.6.2 Replacing whole packages, forcing their removal">
<link href="ch-sharedlibs.html#s-ldconfig" rel="subsection" title="8.1.1 <samp>ldconfig</samp>">
<link href="ch-sharedlibs.html#s8.6.1" rel="subsection" title="8.6.1 The <samp>shlibs</samp> files present on the system">
<link href="ch-sharedlibs.html#s8.6.2" rel="subsection" title="8.6.2 How to use <code>dpkg-shlibdeps</code> and the <code>shlibs</code> files">
<link href="ch-sharedlibs.html#s-shlibs" rel="subsection" title="8.6.3 The <code>shlibs</code> File Format">
<link href="ch-sharedlibs.html#s8.6.4" rel="subsection" title="8.6.4 Providing a <code>shlibs</code> file">
<link href="ch-sharedlibs.html#s-shlibslocal" rel="subsection" title="8.6.5 Writing the <code>debian/shlibs.local</code> file">
<link href="ch-opersys.html#s-fhs" rel="subsection" title="9.1.1 File System Structure">
<link href="ch-opersys.html#s9.1.2" rel="subsection" title="9.1.2 Site-specific programs">
<link href="ch-opersys.html#s9.1.3" rel="subsection" title="9.1.3 The system-wide mail directory">
<link href="ch-opersys.html#s9.2.1" rel="subsection" title="9.2.1 Introduction">
<link href="ch-opersys.html#s9.2.2" rel="subsection" title="9.2.2 UID and GID classes">
<link href="ch-opersys.html#s-/etc/init.d" rel="subsection" title="9.3.1 Introduction">
<link href="ch-opersys.html#s9.3.2" rel="subsection" title="9.3.2 Writing the scripts">
<link href="ch-opersys.html#s9.3.3" rel="subsection" title="9.3.3 Interfacing with the initscript system">
<link href="ch-opersys.html#s9.3.3.1" rel="subsection" title="9.3.3.1 Managing the links">
<link href="ch-opersys.html#s9.3.3.2" rel="subsection" title="9.3.3.2 Running initscripts">
<link href="ch-opersys.html#s9.3.4" rel="subsection" title="9.3.4 Boot-time initialization">
<link href="ch-opersys.html#s9.3.5" rel="subsection" title="9.3.5 Example">
<link href="ch-files.html#s10.7.1" rel="subsection" title="10.7.1 Definitions">
<link href="ch-files.html#s10.7.2" rel="subsection" title="10.7.2 Location">
<link href="ch-files.html#s10.7.3" rel="subsection" title="10.7.3 Behavior">
<link href="ch-files.html#s10.7.4" rel="subsection" title="10.7.4 Sharing configuration files">
<link href="ch-files.html#s10.7.5" rel="subsection" title="10.7.5 User configuration files (&quot;dotfiles&quot;)">
<link href="ch-files.html#s10.9.1" rel="subsection" title="10.9.1 The use of <code>dpkg-statoverride</code>">
<link href="ch-customized-programs.html#s11.8.1" rel="subsection" title="11.8.1 Providing X support and package priorities">
<link href="ch-customized-programs.html#s11.8.2" rel="subsection" title="11.8.2 Packages providing an X server">
<link href="ch-customized-programs.html#s11.8.3" rel="subsection" title="11.8.3 Packages providing a terminal emulator">
<link href="ch-customized-programs.html#s11.8.4" rel="subsection" title="11.8.4 Packages providing a window manager">
<link href="ch-customized-programs.html#s11.8.5" rel="subsection" title="11.8.5 Packages providing fonts">
<link href="ch-customized-programs.html#s11.8.6" rel="subsection" title="11.8.6 Application defaults files">
<link href="ch-customized-programs.html#s11.8.7" rel="subsection" title="11.8.7 Installation directory issues">
<link href="ch-customized-programs.html#s11.8.8" rel="subsection" title="11.8.8 The OSF/Motif and OpenMotif libraries">
<link href="ch-customized-programs.html#s11.8.9" rel="subsection" title="11.8.9 Icon caching">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-source" rel="subsection" title="C.1.1 <code>dpkg-source</code> - packs and unpacks Debian source packages">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-buildpackage" rel="subsection" title="C.1.2 <code>dpkg-buildpackage</code> - overall package-building control script">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-gencontrol" rel="subsection" title="C.1.3 <code>dpkg-gencontrol</code> - generates binary package control files">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-shlibdeps" rel="subsection" title="C.1.4 <code>dpkg-shlibdeps</code> - calculates shared library dependencies">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-distaddfile" rel="subsection" title="C.1.5 <code>dpkg-distaddfile</code> - adds a file to <code>debian/files</code>">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-genchanges" rel="subsection" title="C.1.6 <code>dpkg-genchanges</code> - generates a <code>.changes</code> upload control file">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-parsechangelog" rel="subsection" title="C.1.7 <code>dpkg-parsechangelog</code> - produces parsed representation of a changelog">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkg-architecture" rel="subsection" title="C.1.8 <code>dpkg-architecture</code> - information about the build and host system">
<link href="ap-pkg-sourcepkg.html#s-pkg-debianrules" rel="subsection" title="C.2.1 <code>debian/rules</code> - the main building script">
<link href="ap-pkg-sourcepkg.html#s-pkg-dpkgchangelog" rel="subsection" title="C.2.2 <code>debian/changelog</code>">
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<p><a name="ap-pkg-alternatives"></a></p>
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<h1>
Ubuntu Policy Manual
<br>Appendix F - Alternative versions of an interface - <code>update-alternatives</code> (from old Packaging Manual)</h1>

<hr>

<p>
When several packages all provide different versions of the same program or
file it is useful to have the system select a default, but to allow the system
administrator to change it and have their decisions respected.
</p>

<p>
For example, there are several versions of the <code>vi</code> editor, and
there is no reason to prevent all of them from being installed at once, each
under their own name (<code>nvi</code>, <code>vim</code> or whatever).
Nevertheless it is desirable to have the name <samp>vi</samp> refer to
something, at least by default.
</p>

<p>
If all the packages involved cooperate, this can be done with
<code>update-alternatives</code>.
</p>

<p>
Each package provides its own version under its own name, and calls
<code>update-alternatives</code> in its postinst to register its version (and
again in its prerm to deregister it).
</p>

<p>
See the man page <code>update-alternatives(8)</code> for details.
</p>

<p>
If <code>update-alternatives</code> does not seem appropriate you may wish to
consider using diversions instead.
</p>

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<p>
Ubuntu Policy Manual
</p>

<address>
version 3.8.2.0ubuntu1, 2009-06-19<br>
<br>
<a href="ch-scope.html#s-authors">The Debian Policy Mailing List</a><br>
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