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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    2. 

  2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title xmlns:d="http://docbook.org/ns/docbook">5.4. Manipulating Packages with dpkg</title><link rel="stylesheet" type="text/css" href="Common_Content/css/default.css" /><link rel="stylesheet" media="print" href="Common_Content/css/print.css" type="text/css" /><meta xmlns:d="http://docbook.org/ns/docbook" name="generator" content="publican v4.3.2" /><meta xmlns:d="http://docbook.org/ns/docbook" name="package" content="Debian-debian-handbook-10-en-US-1.0-1" /><meta name="keywords" content="Binary package, Source package, dpkg, deb, dependencies, conflict" /><link rel="home" href="index.html" title="The Debian Administrator's Handbook" /><link rel="up" href="packaging-system.html" title="Chapter 5. Packaging System: Tools and Fundamental Principles" /><link rel="prev" href="sect.source-package-structure.html" title="5.3. Structure of a Source Package" /><link rel="next" href="sect.coexistence-with-other-packaging-systems.html" title="5.5. Coexistence with Other Packaging Systems" /><meta xmlns="" name="flattr:id" content="4pz9jq" /><link xmlns="" rel="canonical" href="https://debian-handbook.info/browse/stable/sect.manipulating-packages-with-dpkg.html" /></head><body><div id="banner"><a href="http://debian-handbook.info/get/"><span class="text">Download the ebook</span></a></div><p id="title"><a class="left" href="http://www.debian.org"><img alt="Product Site" src="Common_Content/images//image_left.png" /></a><a class="right" href="index.html"><img alt="Documentation Site" src="Common_Content/images//image_right.png" /></a></p><ul class="docnav top"><li class="previous"><a accesskey="p" href="sect.source-package-structure.html"><strong>Prev</strong></a></li><li class="home">The Debian Administrator's Handbook</li><li class="next"><a accesskey="n" href="sect.coexistence-with-other-packaging-systems.html"><strong>Next</strong></a></li></ul><div class="section"><div class="titlepage"><div><div><h2 class="title"><a xmlns="" id="sect.manipulating-packages-with-dpkg"></a>5.4. Manipulating Packages with <code class="command">dpkg</code></h2></div></div></div><a id="id-1.8.8.2" class="indexterm"></a><div class="para">
    3. 

  3. 			<code class="command">dpkg</code> is the base command for handling Debian packages on the system. If you have <code class="filename">.deb</code> packages, it is <code class="command">dpkg</code> that allows installation or analysis of their contents. But this program only has a partial view of the Debian universe: it knows what is installed on the system, and whatever it is given on the command line, but knows nothing of the other available packages. As such, it will fail if a dependency is not met. Tools such as <code class="command">apt</code> and <code class="command">aptitude</code>, on the contrary, will create a list of dependencies to install everything as automatically as possible.
    4. 

  4. 		</div><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>NOTE</em></span> <code class="command">dpkg</code> or <code class="command">apt</code>?</strong></p></div></div></div><div class="para">
    5. 

  5. 			<code class="command">dpkg</code> should be seen as a system tool (backend), and <code class="command">apt</code> as a tool closer to the user, which overcomes the limitations of the former. These tools work together, each one with its particularities, suited to specific tasks.
    6. 

  6. 		</div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a xmlns="" id="id-1.8.8.5"></a>5.4.1. Installing Packages</h3></div></div></div><a id="id-1.8.8.5.2" class="indexterm"></a><a id="id-1.8.8.5.3" class="indexterm"></a><div class="para">
    7. 

  7. 				<code class="command">dpkg</code> is, above all, the tool for installing an already available Debian package (because it does not download anything). To do this, we use its <code class="literal">-i</code> or <code class="literal">--install</code> option.
    8. 

  8. 			</div><div class="example"><a xmlns="" id="id-1.8.8.5.5"></a><p class="title"><strong>Example 5.2. Installation of a package with <code class="command">dpkg</code></strong></p><div class="example-contents"><pre class="screen scale">
    9. 

  9. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg -i man-db_2.8.5-2_amd64.deb</code></strong>
    10. 

  10. <code class="computeroutput">(Reading database ... 14913 files and directories currently installed.)
    11. 

  11. Preparing to unpack .../man-db_2.8.5-2_amd64.deb ...
    12. 

  12. Unpacking man-db (2.8.5-2) over (2.8.5-2) ...
    13. 

  13. Setting up man-db (2.8.5-2) ...
    14. 

  14. Updating database of manual pages ...
    15. 

  15. Processing triggers for mime-support (3.62) ...</code></pre></div></div><div class="para">
    16. 

  16. 				We can see the different steps performed by <code class="command">dpkg</code>; we know, thus, at what point any error may have occurred. The installation can also be effected in two stages: first unpacking, then configuration. <code class="command">apt</code> takes advantage of this, limiting the number of calls to <code class="command">dpkg</code> (since each call is costly, due to loading of the database in memory, especially the list of already installed files).
    17. 

  17. 			</div><div class="example"><a xmlns="" id="id-1.8.8.5.7"></a><p class="title"><strong>Example 5.3. Separate unpacking and configuration</strong></p><div class="example-contents"><pre class="screen scale">
    18. 

  18. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg --unpack man-db_2.8.5-2_amd64.deb</code></strong>
    19. 

  19. <code class="computeroutput">(Reading database ... 14937 files and directories currently installed.)
    20. 

  20. Preparing to unpack man-db_2.8.5-2_amd64.deb ...
    21. 

  21. Unpacking man-db (2.8.5-2) over (2.8.5-2) ...
    22. 

  22. Processing triggers for mime-support (3.62) ...
    23. 

  23. # </code><strong class="userinput"><code>dpkg --configure man-db</code></strong>
    24. 

  24. <code class="computeroutput">Setting up man-db (2.8.5-2) ...
    25. 

  25. Updating database of manual pages ...
    26. 

  26. </code></pre></div></div><a id="id-1.8.8.5.8" class="indexterm"></a><a id="id-1.8.8.5.9" class="indexterm"></a><div class="para">
    27. 

  27. 				Sometimes <code class="command">dpkg</code> will fail to install a package and return an error; if the user orders it to ignore this, it will only issue a warning; it is for this reason that we have the different <code class="literal">--force-*</code> options. The <code class="command">dpkg --force-help</code> command, or documentation of this command, will give a complete list of these options. The most frequent error, which you are bound to encounter sooner or later, is a file collision. When a package contains a file that is already installed by another package, <code class="command">dpkg</code> will refuse to install it. The following messages will then appear:
    28. 

  28. 			</div><pre class="screen">
    29. 

  29. <code class="computeroutput">Unpacking libgdm (from .../libgdm_3.8.3-2_amd64.deb) ...
    30. 

  30. dpkg: error processing /var/cache/apt/archives/libgdm_3.8.3-2_amd64.deb (--unpack):
    31. 

  31.  trying to overwrite '/usr/bin/gdmflexiserver', which is also in package gdm3 3.4.1-9</code></pre><div class="para">
    32. 

  32. 				In this case, if you think that replacing this file is not a significant risk to the stability of your system (which is usually the case), you can use the option <code class="literal">--force-overwrite</code>, which tells <code class="command">dpkg</code> to ignore this error and overwrite the file.
    33. 

  33. 			</div><div class="para">
    34. 

  34. 				While there are many available <code class="literal">--force-*</code> options, only <code class="literal">--force-overwrite</code> is likely to be used regularly. These options only exist for exceptional situations, and it is better to leave them alone as much as possible in order to respect the rules imposed by the packaging mechanism. Do not forget, these rules ensure the consistency and stability of your system.
    35. 

  35. 			</div><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>CAUTION</em></span> Effective use of <code class="literal">--force-*</code></strong></p></div></div></div><a id="id-1.8.8.5.14.2" class="indexterm"></a><div class="para">
    36. 

  36. 				If you are not careful, the use of an option <code class="literal">--force-*</code> can lead to a system where the APT family of commands will refuse to function. In effect, some of these options allow installation of a package when a dependency is not met, or when there is a conflict. The result is an inconsistent system from the point of view of dependencies, and the APT commands will refuse to execute any action except those that will bring the system back to a consistent state (this often consists of installing the missing dependency or removing a problematic package). This often results in a message like this one, obtained after installing a new version of <span class="pkg pkg">rdesktop</span> while ignoring its dependency on a newer version of the <span class="pkg pkg">libc6</span>:
    37. 

  37. 			</div><pre class="screen"><code class="computeroutput"># </code><strong class="userinput"><code>apt full-upgrade
    38. 

  38. </code></strong><code class="computeroutput">[...]
    39. 

  39. You might want to run 'apt-get -f install' to correct these.
    40. 

  40. The following packages have unmet dependencies:
    41. 

  41.   rdesktop: Depends: libc6 (&gt;= 2.5) but 2.3.6.ds1-13etch7 is installed
    42. 

  42. E: Unmet dependencies. Try using -f.</code></pre><div class="para">
    43. 

  43. 				A courageous administrator who is certain of the correctness of their analysis may choose to ignore a dependency or conflict and use the corresponding <code class="literal">--force-*</code> option. In this case, if they want to be able to continue to use <code class="command">apt</code> or <code class="command">aptitude</code>, they must edit <code class="filename">/var/lib/dpkg/status</code> to delete/modify the dependency, or conflict, that they chose to override.
    44. 

  44. 			</div><div class="para">
    45. 

  45. 				This manipulation is an ugly hack, and should never be used, except in the most extreme case of necessity. Quite frequently, a more fitting solution is to recompile the package that is causing the problem (see <a class="xref" href="debian-packaging.html#sect.rebuilding-package">Section 15.1, “Rebuilding a Package from its Sources”</a>) or use a new version (potentially corrected) from a repository such as the <code class="literal">stable-backports</code> one (see <a class="xref" href="apt.html#sect.apt-sources.list.stable.backports">Section 6.1.2.4, “Stable Backports”</a>).
    46. 

  46. 			</div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a xmlns="" id="id-1.8.8.6"></a>5.4.2. Package Removal</h3></div></div></div><a id="id-1.8.8.6.2" class="indexterm"></a><a id="id-1.8.8.6.3" class="indexterm"></a><a id="id-1.8.8.6.4" class="indexterm"></a><a id="id-1.8.8.6.5" class="indexterm"></a><div class="para">
    47. 

  47. 				Invoking <code class="command">dpkg</code> with the <code class="literal">-r</code> or <code class="literal">--remove</code> option, followed by the name of a package, removes that package. This removal is, however, not complete: all of the configuration files, maintainer scripts, log files (system logs) and other user data handled by the package remain. That way disabling the program is easily done by uninstalling it, and it is still possible to quickly reinstall it with the same configuration. To completely remove everything associated with a package, use the <code class="literal">-P</code> or <code class="literal">--purge</code> option, followed by the package name.
    48. 

  48. 			</div><div class="example"><a xmlns="" id="id-1.8.8.6.7"></a><p class="title"><strong>Example 5.4. Removal and purge of the <span class="pkg pkg">debian-cd</span> package</strong></p><div class="example-contents"><pre class="screen"><code class="computeroutput"># </code><strong class="userinput"><code>dpkg -r debian-cd</code></strong>
    49. 

  49. <code class="computeroutput">(Reading database ... 15915 files and directories currently installed.)
    50. 

  50. Removing debian-cd (3.1.25) ...
    51. 

  51. # </code><strong class="userinput"><code>dpkg -P debian-cd</code></strong>
    52. 

  52. <code class="computeroutput">(Reading database ... 15394 files and directories currently installed.)
    53. 

  53. Purging configuration files for debian-cd (3.1.25) ...
    54. 

  54. </code></pre></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a xmlns="" id="sect.dpkg-list"></a>5.4.3. Querying <code class="command">dpkg</code>'s Database and Inspecting <code class="filename">.deb</code> Files</h3></div></div></div><a id="id-1.8.8.7.2" class="indexterm"></a><a id="id-1.8.8.7.3" class="indexterm"></a><a id="id-1.8.8.7.4" class="indexterm"></a><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>BACK TO BASICS</em></span> Option syntax</strong></p></div></div></div><div class="para">
    55. 

  55. 				Most options are available in a “long” version (one or more relevant words, preceded by a double dash) and a “short” version (a single letter, often the initial of one word from the long version, and preceded by a single dash). This convention is so common that it is a POSIX standard.
    56. 

  56. 			</div></div><div class="para">
    57. 

  57. 				Before concluding this section, we will study <code class="command">dpkg</code> options that query the internal database in order to obtain information. Giving first the long options and then corresponding short options (that will evidently take the same possible arguments) we cite <code class="literal">--listfiles <em class="replaceable">package</em></code> (or <code class="literal">-L</code>), which lists the files installed by this package; <code class="literal">--search <em class="replaceable">file</em></code> (or <code class="literal">-S</code>), which finds the package(s) containing the file; <code class="literal">--status <em class="replaceable">package</em></code> (or <code class="literal">-s</code>), which displays the headers of an installed package; <code class="literal">--list</code> (or <code class="literal">-l</code>), which displays the list of packages known to the system and their installation status; <code class="literal">--contents <em class="replaceable">file.deb</em></code> (or <code class="literal">-c</code>), which lists the files in the Debian package specified; <code class="literal">--info<em class="replaceable"> file.deb </em></code> (or <code class="literal">-I</code>), which displays the headers of this Debian package.
    58. 

  58. 			</div><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>CAUTION</em></span> <code class="command">dpkg --search</code> and merged <code class="filename">/usr</code></strong></p></div></div></div><a id="id-1.8.8.7.7.2" class="indexterm"></a><a id="id-1.8.8.7.7.3" class="indexterm"></a><div class="para">
    59. 

  59. 				For <a href="https://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/">various reasons</a>, Debian now installs by default a few top-level directories as symlinks to their counterparts below <code class="filename">/usr</code>. For instance, <code class="filename">/bin</code>, <code class="filename">/sbin</code> and <code class="filename">/lib</code> are now symlinks to, respectively, <code class="filename">/usr/bin</code>, <code class="filename">/usr/sbin</code> and <code class="filename">/usr/lib</code>.
    60. 

  60. 			</div><div class="para">
    61. 

  61. 				While this does provide desirable benefits, it can also be a source of confusion. For example, when you query <code class="command">dpkg</code> which package is owning a given file, it will only be able to answer when you ask for its original path:
    62. 

  62. 			</div><pre class="screen">
    63. 

  63. $ <strong class="userinput"><code>dpkg --search /bin/mount</code></strong>
    64. 

  64. mount: /bin/mount
    65. 

  65. $ <strong class="userinput"><code>dpkg --search /usr/bin/mount</code></strong>
    66. 

  66. dpkg-query: no path found matching pattern /usr/bin/mount
    67. 

  67. $ <strong class="userinput"><code>dpkg --search /bin/apt</code></strong>
    68. 

  68. dpkg-query: no path found matching pattern /bin/apt
    69. 

  69. $ <strong class="userinput"><code>dpkg --search /usr/bin/apt</code></strong>
    70. 

  70. apt: /usr/bin/apt
    71. 

  71. </pre></div><div class="example"><a xmlns="" id="id-1.8.8.7.8"></a><p class="title"><strong>Example 5.5. Various queries with <code class="command">dpkg</code></strong></p><div class="example-contents"><pre class="screen scale" width="80">
    72. 

  72. <code class="computeroutput">$ </code><strong class="userinput"><code>dpkg -L base-passwd</code></strong>
    73. 

  73. <code class="computeroutput">/.
    74. 

  74. /usr
    75. 

  75. /usr/sbin
    76. 

  76. /usr/sbin/update-passwd
    77. 

  77. /usr/share
    78. 

  78. /usr/share/base-passwd
    79. 

  79. /usr/share/base-passwd/group.master
    80. 

  80. /usr/share/base-passwd/passwd.master
    81. 

  81. /usr/share/doc
    82. 

  82. /usr/share/doc/base-passwd
    83. 

  83. /usr/share/doc/base-passwd/README
    84. 

  84. /usr/share/doc/base-passwd/changelog.gz
    85. 

  85. /usr/share/doc/base-passwd/copyright
    86. 

  86. /usr/share/doc/base-passwd/users-and-groups.html
    87. 

  87. /usr/share/doc/base-passwd/users-and-groups.txt.gz
    88. 

  88. /usr/share/doc-base
    89. 

  89. /usr/share/doc-base/users-and-groups
    90. 

  90. /usr/share/lintian
    91. 

  91. /usr/share/lintian/overrides
    92. 

  92. /usr/share/lintian/overrides/base-passwd
    93. 

  93. /usr/share/man
    94. 

  94. /usr/share/man/de
    95. 

  95. /usr/share/man/de/man8
    96. 

  96. /usr/share/man/de/man8/update-passwd.8.gz
    97. 

  97. /usr/share/man/es
    98. 

  98. /usr/share/man/es/man8
    99. 

  99. /usr/share/man/es/man8/update-passwd.8.gz
    100. 

  100. /usr/share/man/fr
    101. 

  101. /usr/share/man/fr/man8
    102. 

  102. /usr/share/man/fr/man8/update-passwd.8.gz
    103. 

  103. /usr/share/man/ja
    104. 

  104. /usr/share/man/ja/man8
    105. 

  105. /usr/share/man/ja/man8/update-passwd.8.gz
    106. 

  106. /usr/share/man/man8
    107. 

  107. /usr/share/man/man8/update-passwd.8.gz
    108. 

  108. /usr/share/man/pl
    109. 

  109. /usr/share/man/pl/man8
    110. 

  110. /usr/share/man/pl/man8/update-passwd.8.gz
    111. 

  111. /usr/share/man/ru
    112. 

  112. /usr/share/man/ru/man8
    113. 

  113. /usr/share/man/ru/man8/update-passwd.8.gz
    114. 

  114. $ </code><strong class="userinput"><code>dpkg -S /bin/date</code></strong>
    115. 

  115. <code class="computeroutput">coreutils: /bin/date
    116. 

  116. $ </code><strong class="userinput"><code>dpkg -s coreutils</code></strong>
    117. 

  117. <code class="computeroutput">Package: coreutils
    118. 

  118. Essential: yes
    119. 

  119. Status: install ok installed
    120. 

  120. Priority: required
    121. 

  121. Section: utils
    122. 

  122. Installed-Size: 15719
    123. 

  123. Maintainer: Michael Stone &lt;mstone@debian.org&gt;
    124. 

  124. Architecture: amd64
    125. 

  125. Multi-Arch: foreign
    126. 

  126. Version: 8.30-3
    127. 

  127. Pre-Depends: libacl1 (&gt;= 2.2.23), libattr1 (&gt;= 1:2.4.44), libc6 (&gt;= 2.28), libselinux1 (&gt;= 2.1.13)
    128. 

  128. Description: GNU core utilities
    129. 

  129.  This package contains the basic file, shell and text manipulation
    130. 

  130.  utilities which are expected to exist on every operating system.
    131. 

  131.  .
    132. 

  132.  Specifically, this package includes:
    133. 

  133.  arch base64 basename cat chcon chgrp chmod chown chroot cksum comm cp
    134. 

  134.  csplit cut date dd df dir dircolors dirname du echo env expand expr
    135. 

  135.  factor false flock fmt fold groups head hostid id install join link ln
    136. 

  136.  logname ls md5sum mkdir mkfifo mknod mktemp mv nice nl nohup nproc numfmt
    137. 

  137.  od paste pathchk pinky pr printenv printf ptx pwd readlink realpath rm
    138. 

  138.  rmdir runcon sha*sum seq shred sleep sort split stat stty sum sync tac
    139. 

  139.  tail tee test timeout touch tr true truncate tsort tty uname unexpand
    140. 

  140.  uniq unlink users vdir wc who whoami yes
    141. 

  141. Homepage: http://gnu.org/software/coreutils
    142. 

  142. $ </code><strong class="userinput"><code>dpkg -l 'b*'</code></strong>
    143. 

  143. <code class="computeroutput">Desired=Unknown/Install/Remove/Purge/Hold
    144. 

  144. | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
    145. 

  145. |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
    146. 

  146. ||/ Name                       Version              Architecture Description
    147. 

  147. +++-====================-===============-===============-==================================================
    148. 

  148. un  backupninja          &lt;none&gt;          &lt;none&gt;          (no description available)
    149. 

  149. un  backuppc             &lt;none&gt;          &lt;none&gt;          (no description available)
    150. 

  150. un  baobab               &lt;none&gt;          &lt;node&gt;          (no description available)
    151. 

  151. un  base                 &lt;none&gt;          &lt;none&gt;          (no description available)
    152. 

  152. un  base-config          &lt;none&gt;          &lt;none&gt;          (no description available)
    153. 

  153. ii  base-files           11              amd64           Debian base system miscellaneous files
    154. 

  154. ii  base-passwd          3.5.46          amd64           Debian base system master password and group files
    155. 

  155. ii  bash                 5.0-4           amd64           GNU Bourne Again SHell
    156. 

  156. [..]
    157. 

  157. $ </code><strong class="userinput"><code>dpkg -c /var/cache/apt/archives/gnupg-utils_2.2.12-1_amd64.deb</code></strong>
    158. 

  158. <code class="computeroutput">drwxr-xr-x root/root         0 2018-12-15 02:17 ./
    159. 

  159. drwxr-xr-x root/root         0 2018-12-15 02:17 ./usr/
    160. 

  160. drwxr-xr-x root/root         0 2018-12-15 02:17 ./usr/bin/
    161. 

  161. -rwxr-xr-x root/root      3516 2018-12-15 02:17 ./usr/bin/gpg-zip
    162. 

  162. -rwxr-xr-x root/root    866256 2018-12-15 02:17 ./usr/bin/gpgcompose
    163. 

  163. -rwxr-xr-x root/root     30792 2018-12-15 02:17 ./usr/bin/gpgparsemail
    164. 

  164. -rwxr-xr-x root/root     84432 2018-12-15 02:17 ./usr/bin/gpgsplit
    165. 

  165. -rwxr-xr-x root/root    154952 2018-12-15 02:17 ./usr/bin/gpgtar
    166. 

  166. -rwxr-xr-x root/root    166568 2018-12-15 02:17 ./usr/bin/kbxutil
    167. 

  167. -rwxr-xr-x root/root      1081 2017-08-28 12:22 ./usr/bin/lspgpot
    168. 

  168. -rwxr-xr-x root/root      2194 2018-11-18 23:37 ./usr/bin/migrate-pubring-from-classic-gpg
    169. 

  169. -rwxr-xr-x root/root    121576 2018-12-15 02:17 ./usr/bin/symcryptrun
    170. 

  170. -rwxr-xr-x root/root     18424 2018-12-15 02:17 ./usr/bin/watchgnupg
    171. 

  171. drwxr-xr-x root/root         0 2018-12-15 02:17 ./usr/sbin/
    172. 

  172. -rwxr-xr-x root/root      3075 2018-12-15 02:17 ./usr/sbin/addgnupghome
    173. 

  173. -rwxr-xr-x root/root      2217 2018-12-15 02:17 ./usr/sbin/applygnupgdefaults
    174. 

  174. drwxr-xr-x root/root         0 2018-12-15 02:17 ./usr/share/
    175. 

  175. drwxr-xr-x root/root         0 2018-12-15 02:17 ./usr/share/doc/
    176. 

  176. [...]
    177. 

  177. $ </code><strong class="userinput"><code>dpkg -I /var/cache/apt/archives/gnupg-utils_2.2.12-1_amd64.deb</code></strong>
    178. 

  178. <code class="computeroutput"> new Debian package, version 2.0.
    179. 

  179.  size 857408 bytes: control archive=1844 bytes.
    180. 

  180.     1564 bytes,    32 lines      control              
    181. 

  181.     1804 bytes,    28 lines      md5sums              
    182. 

  182.  Package: gnupg-utils
    183. 

  183.  Source: gnupg2
    184. 

  184.  Version: 2.2.12-1
    185. 

  185.  Architecture: amd64
    186. 

  186.  Maintainer: Debian GnuPG Maintainers &lt;pkg-gnupg-maint@lists.alioth.debian.org&gt;
    187. 

  187.  Installed-Size: 1845
    188. 

  188.  Depends: libassuan0 (&gt;= 2.0.1), libbz2-1.0, libc6 (&gt;= 2.25), libgcrypt20 (&gt;= 1.8.0), libgpg-error0 (&gt;= 1.26-2~), libksba8 (&gt;= 1.3.4), libreadline7 (&gt;= 6.0), zlib1g (&gt;= 1:1.1.4)
    189. 

  189.  Recommends: gpg, gpg-agent, gpgconf, gpgsm
    190. 

  190.  Breaks: gnupg (&lt;&lt; 2.1.21-4), gnupg-agent (&lt;&lt; 2.1.21-4)
    191. 

  191.  Replaces: gnupg (&lt;&lt; 2.1.21-4), gnupg-agent (&lt;&lt; 2.1.21-4)
    192. 

  192.  Section: utils
    193. 

  193.  Priority: optional
    194. 

  194.  Multi-Arch: foreign
    195. 

  195.  Homepage: https://www.gnupg.org/
    196. 

  196.  Description: GNU privacy guard - utility programs
    197. 

  197.   GnuPG is GNU's tool for secure communication and data storage.
    198. 

  198.   .
    199. 

  199.   This package contains several useful utilities for manipulating
    200. 

  200.   OpenPGP data and other related cryptographic elements.  It includes:
    201. 

  201.   .
    202. 

  202.    * addgnupghome -- create .gnupg home directories
    203. 

  203.    * applygnupgdefaults -- run gpgconf --apply-defaults for all users
    204. 

  204.    * gpgcompose -- an experimental tool for constructing arbitrary
    205. 

  205.                    sequences of OpenPGP packets (e.g. for testing)
    206. 

  206.    * gpgparsemail -- parse an e-mail message into annotated format
    207. 

  207.    * gpgsplit -- split a sequence of OpenPGP packets into files
    208. 

  208.    * gpgtar -- encrypt or sign files in an archive
    209. 

  209.    * kbxutil -- list, export, import Keybox data
    210. 

  210.    * lspgpot -- convert PGP ownertrust values to GnuPG
    211. 

  211.    * migrate-pubring-from-classic-gpg -- use only "modern" formats
    212. 

  212.    * symcryptrun -- use simple symmetric encryption tool in GnuPG framework
    213. 

  213.    * watchgnupg -- watch socket-based logs
    214. 

  214. [..]</code></pre></div></div><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>GOING FURTHER</em></span> Comparison of versions</strong></p></div></div></div><a id="id-1.8.8.7.9.2" class="indexterm"></a><a id="id-1.8.8.7.9.3" class="indexterm"></a><a id="id-1.8.8.7.9.4" class="indexterm"></a><div class="para">
    215. 

  215. 				Since <code class="command">dpkg</code> is the program for handling Debian packages, it also provides the reference implementation of the logic of comparing version numbers. This is why it has a <code class="literal">--compare-versions</code> option, usable by external programs (especially configuration scripts executed by <code class="command">dpkg</code> itself). This option requires three parameters: a version number, a comparison operator, and a second version number. The different possible operators are <code class="literal">lt</code> (strictly less than), <code class="literal">le</code> (less than or equal to), <code class="literal">eq</code> (equal), <code class="literal">ne</code> (not equal), <code class="literal">ge</code> (greater than or equal to), and <code class="literal">gt</code> (strictly greater than). If the comparison is correct, <code class="command">dpkg</code> returns 0 (success); if not, it gives a non-zero return value (indicating failure).
    216. 

  216. 			</div><pre class="screen">
    217. 

  217. <code class="computeroutput">$ </code><strong class="userinput"><code>dpkg --compare-versions 1.2-3 gt 1.1-4</code></strong>
    218. 

  218. <code class="computeroutput">$ </code><strong class="userinput"><code>echo $?</code></strong>
    219. 

  219. <code class="computeroutput">0
    220. 

  220. $ </code><strong class="userinput"><code>dpkg --compare-versions 1.2-3 lt 1.1-4</code></strong>
    221. 

  221. <code class="computeroutput">$ </code><strong class="userinput"><code>echo $?</code></strong>
    222. 

  222. <code class="computeroutput">1
    223. 

  223. $ </code><strong class="userinput"><code>dpkg --compare-versions 2.6.0pre3-1 lt 2.6.0-1</code></strong>
    224. 

  224. <code class="computeroutput">$ </code><strong class="userinput"><code>echo $?</code></strong>
    225. 

  225. <code class="computeroutput">1</code></pre><div class="para">
    226. 

  226. 				Note the unexpected failure of the last comparison: for <code class="command">dpkg</code>, <code class="literal">pre</code>, usually denoting a pre-release, has no particular meaning, and this program compares the alphabetic characters in the same way as the numbers (a &lt; b &lt; c ...), in alphabetical order. This is why it considers “<code class="literal">0pre3</code>” to be greater than “<code class="literal">0</code>”. When we want a package's version number to indicate that it is a pre-release, we use the tilde character, “<code class="literal">~</code>”:
    227. 

  227. 			</div><pre class="screen">
    228. 

  228. <code class="computeroutput">$ </code><strong class="userinput"><code>dpkg --compare-versions 2.6.0~pre3-1 lt 2.6.0-1</code></strong>
    229. 

  229. <code class="computeroutput">$ </code><strong class="userinput"><code>echo $?</code></strong>
    230. 

  230. <code class="computeroutput">0</code></pre></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a xmlns="" id="sect.dpkg-log"></a>5.4.4. <code class="command">dpkg</code>'s Log File</h3></div></div></div><a id="id-1.8.8.8.2" class="indexterm"></a><div class="para">
    231. 

  231. 				<code class="command">dpkg</code> keeps a log of all of its actions in <code class="filename">/var/log/dpkg.log</code>. This log is extremely verbose, since it details every one of the stages through which packages handled by <code class="command">dpkg</code> go. In addition to offering a way to track dpkg's behavior, it helps, above all, to keep a history of the development of the system: one can find the exact moment when each package has been installed or updated, and this information can be extremely useful in understanding a recent change in behavior. Additionally, all versions being recorded, it is easy to cross-check the information with the <code class="filename">changelog.Debian.gz</code> for packages in question, or even with online bug reports.
    232. 

  232. 			</div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a xmlns="" id="sect.multi-arch"></a>5.4.5. Multi-Arch Support</h3></div></div></div><a id="id-1.8.8.9.2" class="indexterm"></a><a id="id-1.8.8.9.3" class="indexterm"></a><div class="para">
    233. 

  233. 				All Debian packages have an <code class="literal">Architecture</code> field in their control information. This field can contain either “<code class="literal">all</code>” (for packages that are architecture independent) or the name of the architecture that it targets (like “amd64”, “armhf”, …). In the latter case, by default, <code class="command">dpkg</code> will only accept to install the package if its architecture matches the host's architecture as returned by <code class="command">dpkg --print-architecture</code>.
    234. 

  234. 			</div><div class="para">
    235. 

  235. 				This restriction ensures that users do not end up with binaries compiled for an incorrect architecture. Everything would be perfect except that (some) computers can run binaries for multiple architectures, either natively (an “amd64“ system can run “i386” binaries) or through emulators.
    236. 

  236. 			</div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a xmlns="" id="id-1.8.8.9.6"></a>5.4.5.1. Enabling Multi-Arch</h4></div></div></div><div class="para">
    237. 

  237. 					<code class="command">dpkg</code>'s multi-arch support allows users to define “foreign architectures” that can be installed on the current system. This is simply done with <code class="command">dpkg --add-architecture</code> like in the example below. There is a corresponding <code class="command">dpkg --remove-architecture</code> to drop support of a foreign architecture, but it can only be used when no packages of this architecture remain.
    238. 

  238. 				</div><pre class="screen">
    239. 

  239. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg --print-architecture</code></strong>
    240. 

  240. <code class="computeroutput">amd64
    241. 

  241. # </code><strong class="userinput"><code>dpkg --print-foreign-architectures</code></strong>
    242. 

  242. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg -i gcc-8-base_8.3.0-6_armhf.deb</code></strong>
    243. 

  243. <code class="computeroutput">dpkg: error processing archive gcc-8-base_8.3.0-6_armhf.deb (--install):
    244. 

  244.  package architecture (armhf) does not match system (amd64)
    245. 

  245. Errors were encountered while processing:
    246. 

  246.  gcc-8-base_8.3.0-6_armhf.deb
    247. 

  247. # </code><strong class="userinput"><code>dpkg --add-architecture armhf</code></strong>
    248. 

  248. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg --add-architecture armel</code></strong>
    249. 

  249. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg --print-foreign-architectures</code></strong>
    250. 

  250. <code class="computeroutput">armhf
    251. 

  251. armel
    252. 

  252. # </code><strong class="userinput"><code>dpkg -i gcc-8-base_8.3.0-6_armhf.deb</code></strong>
    253. 

  253. <code class="computeroutput">(Reading database ... 14319 files and directories currently installed.)
    254. 

  254. Preparing to unpack gcc-8-base_8.3.0-6_armhf.deb ...
    255. 

  255. Unpacking gcc-8-base:armhf (8.3.0-6) ...
    256. 

  256. Setting up gcc-8-base:armhf (8.3.0-6) ...
    257. 

  257. # </code><strong class="userinput"><code>dpkg --remove-architecture armhf</code></strong>
    258. 

  258. <code class="computeroutput">dpkg: error: cannot remove architecture 'armhf' currently in use by the database
    259. 

  259. # </code><strong class="userinput"><code>dpkg --remove-architecture armel</code></strong>
    260. 

  260. <code class="computeroutput"># </code><strong class="userinput"><code>dpkg --print-foreign-architectures</code></strong>
    261. 

  261. <code class="computeroutput">armhf</code></pre><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>NOTE</em></span> APT's multi-arch support</strong></p></div></div></div><div class="para">
    262. 

  262. 					APT will automatically detect when dpkg has been configured to support foreign architectures and will start downloading the corresponding <code class="filename">Packages</code> files during its update process.
    263. 

  263. 				</div><div class="para">
    264. 

  264. 					Foreign packages can then be installed with <code class="command">apt install <em class="replaceable">package</em>:<em class="replaceable">architecture</em></code>.
    265. 

  265. 				</div></div><div class="sidebar"><div class="titlepage"><div><div><p class="title"><strong><span class="emphasis"><em>IN PRACTICE</em></span> Using proprietary i386 binaries on amd64</strong></p></div></div></div><div class="para">
    266. 

  266. 					There are multiple use cases for multi-arch, but the most popular ones are the possibility to execute (sometimes proprietary) 32 bit binaries (i386) on 64 bit systems (amd64), and the possibility to cross-compile software for a platform or an architecture different from the host one.
    267. 

  267. 				</div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a xmlns="" id="id-1.8.8.9.7"></a>5.4.5.2. Multi-Arch Related Changes</h4></div></div></div><div class="para">
    268. 

  268. 					To make multi-arch actually useful and usable, libraries had to be repackaged and moved to an architecture-specific directory so that multiple copies (targeting different architectures) can be installed alongside. Such updated packages contain the “<code class="literal">Multi-Arch: same</code>” header field to tell the packaging system that the various architectures of the package can be safely co-installed (and that those packages can only satisfy dependencies of packages of the same architecture). The most important libraries have been converted since the introduction of multi-arch in Debian 7 <span class="distribution distribution">Wheezy</span>, but there are many libraries that will likely never be converted unless someone specifically requests it (through a bug report for example).
    269. 

  269. 				</div><pre class="screen"><code class="computeroutput">$ </code><strong class="userinput"><code>dpkg -s gcc-8-base
    270. 

  270. </code></strong><code class="computeroutput">dpkg-query: error: --status needs a valid package name but 'gcc-8-base' is not: ambiguous package name 'gcc-8-base' with more than one installed instance
    271. 

  271. 

  272. Use --help for help about querying packages.
    273. 

  273. $ </code><strong class="userinput"><code>dpkg -s gcc-8-base:amd64 gcc-8-base:armhf | grep ^Multi
    274. 

  274. </code></strong><code class="computeroutput">Multi-Arch: same
    275. 

  275. Multi-Arch: same
    276. 

  276. $ </code><strong class="userinput"><code>dpkg -L libgcc1:amd64 |grep .so
    277. 

  277. </code></strong><code class="computeroutput">/lib/x86_64-linux-gnu/libgcc_s.so.1
    278. 

  278. $ </code><strong class="userinput"><code>dpkg -S /usr/share/doc/gcc-8-base/copyright
    279. 

  279. </code></strong><code class="computeroutput">gcc-8-base:amd64, gcc-8-base:armhf: /usr/share/doc/gcc-8-base/copyright
    280. 

  280. </code></pre><div class="para">
    281. 

  281. 					It is worth noting that <code class="literal">Multi-Arch: same</code> packages must have their names qualified with their architecture to be unambiguously identifiable. They also have the possibility to share files with other instances of the same package; <code class="command">dpkg</code> ensures that all packages have bit-for-bit identical files when they are shared. Last but not least, all instances of a package must have the same version. They must thus be upgraded together.
    282. 

  282. 				</div><div class="para">
    283. 

  283. 					Multi-Arch support also brings some interesting challenges in the way dependencies are handled. Satisfying a dependency requires either a package marked “<code class="literal">Multi-Arch: foreign</code>” or a package whose architecture matches the one of the package declaring the dependency (in this dependency resolution process, architecture-independent packages are assumed to be of the same architecture than the host). A dependency can also be weakened to allow any architecture to fulfill it, with the <code class="literal"><em class="replaceable">package</em>:any</code> syntax, but foreign packages can only satisfy such a dependency if they are marked “<code class="literal">Multi-Arch: allowed</code>”.
    284. 

  284. 				</div></div></div></div><ul class="docnav"><li class="previous"><a accesskey="p" href="sect.source-package-structure.html"><strong>Prev</strong>5.3. Structure of a Source Package</a></li><li class="up"><a accesskey="u" href="#"><strong>Up</strong></a></li><li class="home"><a accesskey="h" href="index.html"><strong>Home</strong></a></li><li class="next"><a accesskey="n" href="sect.coexistence-with-other-packaging-systems.html"><strong>Next</strong>5.5. Coexistence with Other Packaging Systems</a></li></ul></body></html>
    285.