| 1 | <?xml version="1.0" encoding="utf-8" standalone="no"?> |
| 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
| 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ |
| 4 | |
| 5 | <!ENTITY % aptent SYSTEM "apt.ent"> |
| 6 | %aptent; |
| 7 | |
| 8 | ]> |
| 9 | |
| 10 | <refentry> |
| 11 | |
| 12 | <refentryinfo> |
| 13 | &apt-author.team; |
| 14 | &apt-email; |
| 15 | &apt-product; |
| 16 | <!-- The last update date --> |
| 17 | <date>16 February 2010</date> |
| 18 | </refentryinfo> |
| 19 | |
| 20 | <refmeta> |
| 21 | <refentrytitle>apt_preferences</refentrytitle> |
| 22 | <manvolnum>5</manvolnum> |
| 23 | <refmiscinfo class="manual">APT</refmiscinfo> |
| 24 | </refmeta> |
| 25 | |
| 26 | <!-- Man page title --> |
| 27 | <refnamediv> |
| 28 | <refname>apt_preferences</refname> |
| 29 | <refpurpose>Preference control file for APT</refpurpose> |
| 30 | </refnamediv> |
| 31 | |
| 32 | <refsect1> |
| 33 | <title>Description</title> |
| 34 | <para>The APT preferences file <filename>/etc/apt/preferences</filename> |
| 35 | and the fragment files in the <filename>/etc/apt/preferences.d/</filename> |
| 36 | folder can be used to control which versions of packages will be selected |
| 37 | for installation.</para> |
| 38 | |
| 39 | <para>Several versions of a package may be available for installation when |
| 40 | the &sources-list; file contains references to more than one distribution |
| 41 | (for example, <literal>stable</literal> and <literal>testing</literal>). |
| 42 | APT assigns a priority to each version that is available. |
| 43 | Subject to dependency constraints, <command>apt-get</command> selects the |
| 44 | version with the highest priority for installation. |
| 45 | The APT preferences file overrides the priorities that APT assigns to |
| 46 | package versions by default, thus giving the user control over which |
| 47 | one is selected for installation.</para> |
| 48 | |
| 49 | <para>Several instances of the same version of a package may be available when |
| 50 | the &sources-list; file contains references to more than one source. |
| 51 | In this case <command>apt-get</command> downloads the instance listed |
| 52 | earliest in the &sources-list; file. |
| 53 | The APT preferences file does not affect the choice of instance, only |
| 54 | the choice of version.</para> |
| 55 | |
| 56 | <para>Preferences are a strong power in the hands of a system administrator |
| 57 | but they can become also their biggest nightmare if used without care! |
| 58 | APT will not questioning the preferences so wrong settings will therefore |
| 59 | lead to uninstallable packages or wrong decisions while upgrading packages. |
| 60 | Even more problems will arise if multiply distribution releases are mixed |
| 61 | without a good understanding of the following paragraphs. |
| 62 | Packages included in a specific release aren't tested in and |
| 63 | therefore doesn't always work as expected in older or newer releases or |
| 64 | together with other packages from different releases. |
| 65 | You have been warned.</para> |
| 66 | |
| 67 | <para>Note that the files in the <filename>/etc/apt/preferences.d</filename> |
| 68 | directory are parsed in alphanumeric ascending order and need to obey the |
| 69 | following naming convention: The files have no or "<literal>pref</literal>" |
| 70 | as filename extension and which only contain alphanumeric, hyphen (-), |
| 71 | underscore (_) and period (.) characters - otherwise they will be silently |
| 72 | ignored.</para> |
| 73 | |
| 74 | <refsect2><title>APT's Default Priority Assignments</title> |
| 75 | |
| 76 | <para>If there is no preferences file or if there is no entry in the file |
| 77 | that applies to a particular version then the priority assigned to that |
| 78 | version is the priority of the distribution to which that version |
| 79 | belongs. It is possible to single out a distribution, "the target release", |
| 80 | which receives a higher priority than other distributions do by default. |
| 81 | The target release can be set on the <command>apt-get</command> command |
| 82 | line or in the APT configuration file <filename>/etc/apt/apt.conf</filename>. |
| 83 | Note that this has precedence over any general priority you set in the |
| 84 | <filename>/etc/apt/preferences</filename> file described later, but not |
| 85 | over specifically pinned packages. |
| 86 | For example, |
| 87 | |
| 88 | <programlisting> |
| 89 | <command>apt-get install -t testing <replaceable>some-package</replaceable></command> |
| 90 | </programlisting> |
| 91 | <programlisting> |
| 92 | APT::Default-Release "stable"; |
| 93 | </programlisting> |
| 94 | </para> |
| 95 | |
| 96 | <para>If the target release has been specified then APT uses the following |
| 97 | algorithm to set the priorities of the versions of a package. Assign: |
| 98 | |
| 99 | <variablelist> |
| 100 | <varlistentry> |
| 101 | <term>priority 100</term> |
| 102 | <listitem><simpara>to the version that is already installed (if any).</simpara></listitem> |
| 103 | </varlistentry> |
| 104 | |
| 105 | <varlistentry> |
| 106 | <term>priority 500</term> |
| 107 | <listitem><simpara>to the versions that are not installed and do not belong to the target release.</simpara></listitem> |
| 108 | </varlistentry> |
| 109 | |
| 110 | <varlistentry> |
| 111 | <term>priority 990</term> |
| 112 | <listitem><simpara>to the versions that are not installed and belong to the target release.</simpara></listitem> |
| 113 | </varlistentry> |
| 114 | </variablelist> |
| 115 | </para> |
| 116 | |
| 117 | <para>If the target release has not been specified then APT simply assigns |
| 118 | priority 100 to all installed package versions and priority 500 to all |
| 119 | uninstalled package versions.</para> |
| 120 | |
| 121 | <para>APT then applies the following rules, listed in order of precedence, |
| 122 | to determine which version of a package to install. |
| 123 | <itemizedlist> |
| 124 | <listitem><simpara>Never downgrade unless the priority of an available |
| 125 | version exceeds 1000. ("Downgrading" is installing a less recent version |
| 126 | of a package in place of a more recent version. Note that none of APT's |
| 127 | default priorities exceeds 1000; such high priorities can only be set in |
| 128 | the preferences file. Note also that downgrading a package |
| 129 | can be risky.)</simpara></listitem> |
| 130 | <listitem><simpara>Install the highest priority version.</simpara></listitem> |
| 131 | <listitem><simpara>If two or more versions have the same priority, |
| 132 | install the most recent one (that is, the one with the higher version |
| 133 | number).</simpara></listitem> |
| 134 | <listitem><simpara>If two or more versions have the same priority and |
| 135 | version number but either the packages differ in some of their metadata or the |
| 136 | <literal>--reinstall</literal> option is given, install the uninstalled one.</simpara></listitem> |
| 137 | </itemizedlist> |
| 138 | </para> |
| 139 | |
| 140 | <para>In a typical situation, the installed version of a package (priority 100) |
| 141 | is not as recent as one of the versions available from the sources listed in |
| 142 | the &sources-list; file (priority 500 or 990). Then the package will be upgraded |
| 143 | when <command>apt-get install <replaceable>some-package</replaceable></command> |
| 144 | or <command>apt-get upgrade</command> is executed. |
| 145 | </para> |
| 146 | |
| 147 | <para>More rarely, the installed version of a package is <emphasis>more</emphasis> recent |
| 148 | than any of the other available versions. The package will not be downgraded |
| 149 | when <command>apt-get install <replaceable>some-package</replaceable></command> |
| 150 | or <command>apt-get upgrade</command> is executed.</para> |
| 151 | |
| 152 | <para>Sometimes the installed version of a package is more recent than the |
| 153 | version belonging to the target release, but not as recent as a version |
| 154 | belonging to some other distribution. Such a package will indeed be upgraded |
| 155 | when <command>apt-get install <replaceable>some-package</replaceable></command> |
| 156 | or <command>apt-get upgrade</command> is executed, |
| 157 | because at least <emphasis>one</emphasis> of the available versions has a higher |
| 158 | priority than the installed version.</para> |
| 159 | </refsect2> |
| 160 | |
| 161 | <refsect2><title>The Effect of APT Preferences</title> |
| 162 | |
| 163 | <para>The APT preferences file allows the system administrator to control the |
| 164 | assignment of priorities. The file consists of one or more multi-line records |
| 165 | separated by blank lines. Records can have one of two forms, a specific form |
| 166 | and a general form. |
| 167 | <itemizedlist> |
| 168 | <listitem> |
| 169 | <simpara>The specific form assigns a priority (a "Pin-Priority") to one or more |
| 170 | specified packages and specified version or version range. For example, |
| 171 | the following record assigns a high priority to all versions of |
| 172 | the <filename>perl</filename> package whose version number begins with "<literal>5.8</literal>". |
| 173 | Multiple packages can be separated by spaces.</simpara> |
| 174 | |
| 175 | <programlisting> |
| 176 | Package: perl |
| 177 | Pin: version 5.8* |
| 178 | Pin-Priority: 1001 |
| 179 | </programlisting> |
| 180 | </listitem> |
| 181 | |
| 182 | <listitem><simpara>The general form assigns a priority to all of the package versions in a |
| 183 | given distribution (that is, to all the versions of packages that are |
| 184 | listed in a certain <filename>Release</filename> file) or to all of the package |
| 185 | versions coming from a particular Internet site, as identified by the |
| 186 | site's fully qualified domain name.</simpara> |
| 187 | |
| 188 | <simpara>This general-form entry in the APT preferences file applies only |
| 189 | to groups of packages. For example, the following record assigns a high |
| 190 | priority to all package versions available from the local site.</simpara> |
| 191 | |
| 192 | <programlisting> |
| 193 | Package: * |
| 194 | Pin: origin "" |
| 195 | Pin-Priority: 999 |
| 196 | </programlisting> |
| 197 | |
| 198 | <simpara>A note of caution: the keyword used here is "<literal>origin</literal>" |
| 199 | which can be used to match a hostname. The following record will assign a high priority |
| 200 | to all versions available from the server identified by the hostname "ftp.de.debian.org"</simpara> |
| 201 | <programlisting> |
| 202 | Package: * |
| 203 | Pin: origin "ftp.de.debian.org" |
| 204 | Pin-Priority: 999 |
| 205 | </programlisting> |
| 206 | <simpara>This should <emphasis>not</emphasis> be confused with the Origin of a distribution as |
| 207 | specified in a <filename>Release</filename> file. What follows the "Origin:" tag |
| 208 | in a <filename>Release</filename> file is not an Internet address |
| 209 | but an author or vendor name, such as "Debian" or "Ximian".</simpara> |
| 210 | |
| 211 | <simpara>The following record assigns a low priority to all package versions |
| 212 | belonging to any distribution whose Archive name is "<literal>unstable</literal>".</simpara> |
| 213 | |
| 214 | <programlisting> |
| 215 | Package: * |
| 216 | Pin: release a=unstable |
| 217 | Pin-Priority: 50 |
| 218 | </programlisting> |
| 219 | |
| 220 | <simpara>The following record assigns a high priority to all package versions |
| 221 | belonging to any distribution whose Codename is "<literal>squeeze</literal>".</simpara> |
| 222 | |
| 223 | <programlisting> |
| 224 | Package: * |
| 225 | Pin: release n=squeeze |
| 226 | Pin-Priority: 900 |
| 227 | </programlisting> |
| 228 | |
| 229 | <simpara>The following record assigns a high priority to all package versions |
| 230 | belonging to any release whose Archive name is "<literal>stable</literal>" |
| 231 | and whose release Version number is "<literal>3.0</literal>".</simpara> |
| 232 | |
| 233 | <programlisting> |
| 234 | Package: * |
| 235 | Pin: release a=stable, v=3.0 |
| 236 | Pin-Priority: 500 |
| 237 | </programlisting> |
| 238 | </listitem> |
| 239 | </itemizedlist> |
| 240 | </para> |
| 241 | |
| 242 | </refsect2> |
| 243 | |
| 244 | <refsect2> |
| 245 | <title>How APT Interprets Priorities</title> |
| 246 | |
| 247 | <para> |
| 248 | Priorities (P) assigned in the APT preferences file must be positive |
| 249 | or negative integers. They are interpreted as follows (roughly speaking): |
| 250 | |
| 251 | <variablelist> |
| 252 | <varlistentry> |
| 253 | <term>P > 1000</term> |
| 254 | <listitem><simpara>causes a version to be installed even if this |
| 255 | constitutes a downgrade of the package</simpara></listitem> |
| 256 | </varlistentry> |
| 257 | <varlistentry> |
| 258 | <term>990 < P <=1000</term> |
| 259 | <listitem><simpara>causes a version to be installed |
| 260 | even if it does not come from the target release, |
| 261 | unless the installed version is more recent</simpara></listitem> |
| 262 | </varlistentry> |
| 263 | <varlistentry> |
| 264 | <term>500 < P <=990</term> |
| 265 | <listitem><simpara>causes a version to be installed |
| 266 | unless there is a version available belonging to the target release |
| 267 | or the installed version is more recent</simpara></listitem> |
| 268 | </varlistentry> |
| 269 | <varlistentry> |
| 270 | <term>100 < P <=500</term> |
| 271 | <listitem><simpara>causes a version to be installed |
| 272 | unless there is a version available belonging to some other |
| 273 | distribution or the installed version is more recent</simpara></listitem> |
| 274 | </varlistentry> |
| 275 | <varlistentry> |
| 276 | <term>0 < P <=100</term> |
| 277 | <listitem><simpara>causes a version to be installed |
| 278 | only if there is no installed version of the package</simpara></listitem> |
| 279 | </varlistentry> |
| 280 | <varlistentry> |
| 281 | <term>P < 0</term> |
| 282 | <listitem><simpara>prevents the version from being installed</simpara></listitem> |
| 283 | </varlistentry> |
| 284 | </variablelist> |
| 285 | </para> |
| 286 | |
| 287 | <para>If any specific-form records match an available package version then the |
| 288 | first such record determines the priority of the package version. |
| 289 | Failing that, |
| 290 | if any general-form records match an available package version then the |
| 291 | first such record determines the priority of the package version.</para> |
| 292 | |
| 293 | <para>For example, suppose the APT preferences file contains the three |
| 294 | records presented earlier:</para> |
| 295 | |
| 296 | <programlisting> |
| 297 | Package: perl |
| 298 | Pin: version 5.8* |
| 299 | Pin-Priority: 1001 |
| 300 | |
| 301 | Package: * |
| 302 | Pin: origin "" |
| 303 | Pin-Priority: 999 |
| 304 | |
| 305 | Package: * |
| 306 | Pin: release unstable |
| 307 | Pin-Priority: 50 |
| 308 | </programlisting> |
| 309 | |
| 310 | <para>Then: |
| 311 | <itemizedlist> |
| 312 | <listitem><simpara>The most recent available version of the <literal>perl</literal> |
| 313 | package will be installed, so long as that version's version number begins |
| 314 | with "<literal>5.8</literal>". If <emphasis>any</emphasis> 5.8* version of <literal>perl</literal> is |
| 315 | available and the installed version is 5.9*, then <literal>perl</literal> will be |
| 316 | downgraded.</simpara></listitem> |
| 317 | <listitem><simpara>A version of any package other than <literal>perl</literal> |
| 318 | that is available from the local system has priority over other versions, |
| 319 | even versions belonging to the target release. |
| 320 | </simpara></listitem> |
| 321 | <listitem><simpara>A version of a package whose origin is not the local |
| 322 | system but some other site listed in &sources-list; and which belongs to |
| 323 | an <literal>unstable</literal> distribution is only installed if it is selected |
| 324 | for installation and no version of the package is already installed. |
| 325 | </simpara></listitem> |
| 326 | </itemizedlist> |
| 327 | </para> |
| 328 | </refsect2> |
| 329 | |
| 330 | <refsect2> |
| 331 | <title>Determination of Package Version and Distribution Properties</title> |
| 332 | |
| 333 | <para>The locations listed in the &sources-list; file should provide |
| 334 | <filename>Packages</filename> and <filename>Release</filename> files |
| 335 | to describe the packages available at that location. </para> |
| 336 | |
| 337 | <para>The <filename>Packages</filename> file is normally found in the directory |
| 338 | <filename>.../dists/<replaceable>dist-name</replaceable>/<replaceable>component</replaceable>/<replaceable>arch</replaceable></filename>: |
| 339 | for example, <filename>.../dists/stable/main/binary-i386/Packages</filename>. |
| 340 | It consists of a series of multi-line records, one for each package available |
| 341 | in that directory. Only two lines in each record are relevant for setting |
| 342 | APT priorities: |
| 343 | <variablelist> |
| 344 | <varlistentry> |
| 345 | <term>the <literal>Package:</literal> line</term> |
| 346 | <listitem><simpara>gives the package name</simpara></listitem> |
| 347 | </varlistentry> |
| 348 | <varlistentry> |
| 349 | <term>the <literal>Version:</literal> line</term> |
| 350 | <listitem><simpara>gives the version number for the named package</simpara></listitem> |
| 351 | </varlistentry> |
| 352 | </variablelist> |
| 353 | </para> |
| 354 | |
| 355 | <para>The <filename>Release</filename> file is normally found in the directory |
| 356 | <filename>.../dists/<replaceable>dist-name</replaceable></filename>: |
| 357 | for example, <filename>.../dists/stable/Release</filename>, |
| 358 | or <filename>.../dists/woody/Release</filename>. |
| 359 | It consists of a single multi-line record which applies to <emphasis>all</emphasis> of |
| 360 | the packages in the directory tree below its parent. Unlike the |
| 361 | <filename>Packages</filename> file, nearly all of the lines in a <filename>Release</filename> |
| 362 | file are relevant for setting APT priorities: |
| 363 | |
| 364 | <variablelist> |
| 365 | <varlistentry> |
| 366 | <term>the <literal>Archive:</literal> or <literal>Suite:</literal> line</term> |
| 367 | <listitem><simpara>names the archive to which all the packages |
| 368 | in the directory tree belong. For example, the line |
| 369 | "Archive: stable" or |
| 370 | "Suite: stable" |
| 371 | specifies that all of the packages in the directory |
| 372 | tree below the parent of the <filename>Release</filename> file are in a |
| 373 | <literal>stable</literal> archive. Specifying this value in the APT preferences file |
| 374 | would require the line: |
| 375 | </simpara> |
| 376 | <programlisting> |
| 377 | Pin: release a=stable |
| 378 | </programlisting> |
| 379 | </listitem> |
| 380 | </varlistentry> |
| 381 | |
| 382 | <varlistentry> |
| 383 | <term>the <literal>Codename:</literal> line</term> |
| 384 | <listitem><simpara>names the codename to which all the packages |
| 385 | in the directory tree belong. For example, the line |
| 386 | "Codename: squeeze" |
| 387 | specifies that all of the packages in the directory |
| 388 | tree below the parent of the <filename>Release</filename> file belong to a version named |
| 389 | <literal>squeeze</literal>. Specifying this value in the APT preferences file |
| 390 | would require the line: |
| 391 | </simpara> |
| 392 | <programlisting> |
| 393 | Pin: release n=squeeze |
| 394 | </programlisting> |
| 395 | </listitem> |
| 396 | </varlistentry> |
| 397 | |
| 398 | <varlistentry> |
| 399 | <term>the <literal>Version:</literal> line</term> |
| 400 | <listitem><simpara>names the release version. For example, the |
| 401 | packages in the tree might belong to Debian GNU/Linux release |
| 402 | version 3.0. Note that there is normally no version number for the |
| 403 | <literal>testing</literal> and <literal>unstable</literal> distributions because they |
| 404 | have not been released yet. Specifying this in the APT preferences |
| 405 | file would require one of the following lines. |
| 406 | </simpara> |
| 407 | |
| 408 | <programlisting> |
| 409 | Pin: release v=3.0 |
| 410 | Pin: release a=stable, v=3.0 |
| 411 | Pin: release 3.0 |
| 412 | </programlisting> |
| 413 | |
| 414 | </listitem> |
| 415 | </varlistentry> |
| 416 | |
| 417 | <varlistentry> |
| 418 | <term>the <literal>Component:</literal> line</term> |
| 419 | <listitem><simpara>names the licensing component associated with the |
| 420 | packages in the directory tree of the <filename>Release</filename> file. |
| 421 | For example, the line "Component: main" specifies that |
| 422 | all the packages in the directory tree are from the <literal>main</literal> |
| 423 | component, which entails that they are licensed under terms listed |
| 424 | in the Debian Free Software Guidelines. Specifying this component |
| 425 | in the APT preferences file would require the line: |
| 426 | </simpara> |
| 427 | <programlisting> |
| 428 | Pin: release c=main |
| 429 | </programlisting> |
| 430 | </listitem> |
| 431 | </varlistentry> |
| 432 | |
| 433 | <varlistentry> |
| 434 | <term>the <literal>Origin:</literal> line</term> |
| 435 | <listitem><simpara>names the originator of the packages in the |
| 436 | directory tree of the <filename>Release</filename> file. Most commonly, this is |
| 437 | <literal>Debian</literal>. Specifying this origin in the APT preferences file |
| 438 | would require the line: |
| 439 | </simpara> |
| 440 | <programlisting> |
| 441 | Pin: release o=Debian |
| 442 | </programlisting> |
| 443 | </listitem> |
| 444 | </varlistentry> |
| 445 | |
| 446 | <varlistentry> |
| 447 | <term>the <literal>Label:</literal> line</term> |
| 448 | <listitem><simpara>names the label of the packages in the directory tree |
| 449 | of the <filename>Release</filename> file. Most commonly, this is |
| 450 | <literal>Debian</literal>. Specifying this label in the APT preferences file |
| 451 | would require the line: |
| 452 | </simpara> |
| 453 | <programlisting> |
| 454 | Pin: release l=Debian |
| 455 | </programlisting> |
| 456 | </listitem> |
| 457 | </varlistentry> |
| 458 | </variablelist> |
| 459 | </para> |
| 460 | |
| 461 | <para>All of the <filename>Packages</filename> and <filename>Release</filename> |
| 462 | files retrieved from locations listed in the &sources-list; file are stored |
| 463 | in the directory <filename>/var/lib/apt/lists</filename>, or in the file named |
| 464 | by the variable <literal>Dir::State::Lists</literal> in the <filename>apt.conf</filename> file. |
| 465 | For example, the file |
| 466 | <filename>debian.lcs.mit.edu_debian_dists_unstable_contrib_binary-i386_Release</filename> |
| 467 | contains the <filename>Release</filename> file retrieved from the site |
| 468 | <literal>debian.lcs.mit.edu</literal> for <literal>binary-i386</literal> architecture |
| 469 | files from the <literal>contrib</literal> component of the <literal>unstable</literal> |
| 470 | distribution.</para> |
| 471 | </refsect2> |
| 472 | |
| 473 | <refsect2> |
| 474 | <title>Optional Lines in an APT Preferences Record</title> |
| 475 | |
| 476 | <para>Each record in the APT preferences file can optionally begin with |
| 477 | one or more lines beginning with the word <literal>Explanation:</literal>. |
| 478 | This provides a place for comments.</para> |
| 479 | </refsect2> |
| 480 | </refsect1> |
| 481 | |
| 482 | <refsect1> |
| 483 | <title>Examples</title> |
| 484 | <refsect2> |
| 485 | <title>Tracking Stable</title> |
| 486 | |
| 487 | <para>The following APT preferences file will cause APT to assign a |
| 488 | priority higher than the default (500) to all package versions belonging |
| 489 | to a <literal>stable</literal> distribution and a prohibitively low priority to |
| 490 | package versions belonging to other <literal>Debian</literal> distributions. |
| 491 | |
| 492 | <programlisting> |
| 493 | Explanation: Uninstall or do not install any Debian-originated |
| 494 | Explanation: package versions other than those in the stable distro |
| 495 | Package: * |
| 496 | Pin: release a=stable |
| 497 | Pin-Priority: 900 |
| 498 | |
| 499 | Package: * |
| 500 | Pin: release o=Debian |
| 501 | Pin-Priority: -10 |
| 502 | </programlisting> |
| 503 | </para> |
| 504 | |
| 505 | <para>With a suitable &sources-list; file and the above preferences file, |
| 506 | any of the following commands will cause APT to upgrade to the |
| 507 | latest <literal>stable</literal> version(s). |
| 508 | |
| 509 | <programlisting> |
| 510 | apt-get install <replaceable>package-name</replaceable> |
| 511 | apt-get upgrade |
| 512 | apt-get dist-upgrade |
| 513 | </programlisting> |
| 514 | </para> |
| 515 | |
| 516 | <para>The following command will cause APT to upgrade the specified |
| 517 | package to the latest version from the <literal>testing</literal> distribution; |
| 518 | the package will not be upgraded again unless this command is given |
| 519 | again. |
| 520 | |
| 521 | <programlisting> |
| 522 | apt-get install <replaceable>package</replaceable>/testing |
| 523 | </programlisting> |
| 524 | </para> |
| 525 | </refsect2> |
| 526 | |
| 527 | <refsect2> |
| 528 | <title>Tracking Testing or Unstable</title> |
| 529 | |
| 530 | <para>The following APT preferences file will cause APT to assign |
| 531 | a high priority to package versions from the <literal>testing</literal> |
| 532 | distribution, a lower priority to package versions from the |
| 533 | <literal>unstable</literal> distribution, and a prohibitively low priority |
| 534 | to package versions from other <literal>Debian</literal> distributions. |
| 535 | |
| 536 | <programlisting> |
| 537 | Package: * |
| 538 | Pin: release a=testing |
| 539 | Pin-Priority: 900 |
| 540 | |
| 541 | Package: * |
| 542 | Pin: release a=unstable |
| 543 | Pin-Priority: 800 |
| 544 | |
| 545 | Package: * |
| 546 | Pin: release o=Debian |
| 547 | Pin-Priority: -10 |
| 548 | </programlisting> |
| 549 | </para> |
| 550 | |
| 551 | <para>With a suitable &sources-list; file and the above preferences file, |
| 552 | any of the following commands will cause APT to upgrade to the latest |
| 553 | <literal>testing</literal> version(s). |
| 554 | |
| 555 | <programlisting> |
| 556 | apt-get install <replaceable>package-name</replaceable> |
| 557 | apt-get upgrade |
| 558 | apt-get dist-upgrade |
| 559 | </programlisting> |
| 560 | </para> |
| 561 | |
| 562 | <para>The following command will cause APT to upgrade the specified |
| 563 | package to the latest version from the <literal>unstable</literal> distribution. |
| 564 | Thereafter, <command>apt-get upgrade</command> will upgrade |
| 565 | the package to the most recent <literal>testing</literal> version if that is |
| 566 | more recent than the installed version, otherwise, to the most recent |
| 567 | <literal>unstable</literal> version if that is more recent than the installed |
| 568 | version. |
| 569 | |
| 570 | <programlisting> |
| 571 | apt-get install <replaceable>package</replaceable>/unstable |
| 572 | </programlisting> |
| 573 | </para> |
| 574 | </refsect2> |
| 575 | |
| 576 | |
| 577 | <refsect2> |
| 578 | <title>Tracking the evolution of a codename release</title> |
| 579 | |
| 580 | <para>The following APT preferences file will cause APT to assign a |
| 581 | priority higher than the default (500) to all package versions belonging |
| 582 | to a specified codename of a distribution and a prohibitively low priority to |
| 583 | package versions belonging to other <literal>Debian</literal> distributions, |
| 584 | codenames and archives. |
| 585 | Note that with this APT preference APT will follow the migration of a release |
| 586 | from the archive <literal>testing</literal> to <literal>stable</literal> and |
| 587 | later <literal>oldstable</literal>. If you want to follow for example the progress |
| 588 | in <literal>testing</literal> notwithstanding the codename changes you should use |
| 589 | the example configurations above. |
| 590 | |
| 591 | <programlisting> |
| 592 | Explanation: Uninstall or do not install any Debian-originated package versions |
| 593 | Explanation: other than those in the distribution codenamed with squeeze or sid |
| 594 | Package: * |
| 595 | Pin: release n=squeeze |
| 596 | Pin-Priority: 900 |
| 597 | |
| 598 | Explanation: Debian unstable is always codenamed with sid |
| 599 | Package: * |
| 600 | Pin: release n=sid |
| 601 | Pin-Priority: 800 |
| 602 | |
| 603 | Package: * |
| 604 | Pin: release o=Debian |
| 605 | Pin-Priority: -10 |
| 606 | </programlisting> |
| 607 | </para> |
| 608 | |
| 609 | <para>With a suitable &sources-list; file and the above preferences file, |
| 610 | any of the following commands will cause APT to upgrade to the |
| 611 | latest version(s) in the release codenamed with <literal>squeeze</literal>. |
| 612 | |
| 613 | <programlisting> |
| 614 | apt-get install <replaceable>package-name</replaceable> |
| 615 | apt-get upgrade |
| 616 | apt-get dist-upgrade |
| 617 | </programlisting> |
| 618 | </para> |
| 619 | |
| 620 | <para>The following command will cause APT to upgrade the specified |
| 621 | package to the latest version from the <literal>sid</literal> distribution. |
| 622 | Thereafter, <command>apt-get upgrade</command> will upgrade |
| 623 | the package to the most recent <literal>squeeze</literal> version if that is |
| 624 | more recent than the installed version, otherwise, to the most recent |
| 625 | <literal>sid</literal> version if that is more recent than the installed |
| 626 | version. |
| 627 | |
| 628 | <programlisting> |
| 629 | apt-get install <replaceable>package</replaceable>/sid |
| 630 | </programlisting> |
| 631 | </para> |
| 632 | </refsect2> |
| 633 | </refsect1> |
| 634 | |
| 635 | <refsect1> |
| 636 | <title>Files</title> |
| 637 | <variablelist> |
| 638 | &file-preferences; |
| 639 | </variablelist> |
| 640 | </refsect1> |
| 641 | |
| 642 | <refsect1> |
| 643 | <title>See Also</title> |
| 644 | <para>&apt-get; &apt-cache; &apt-conf; &sources-list; |
| 645 | </para> |
| 646 | </refsect1> |
| 647 | |
| 648 | &manbugs; |
| 649 | |
| 650 | </refentry> |