[f45b1953] | 1 | <sect1 id="intro-important-unpacking">
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| 2 | <?dbhtml filename="unpacking.html" dir="introduction"?>
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[0c603671] | 3 | <title>Notes on downloading, unpacking and compiling software</title>
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[f45b1953] | 4 |
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[acfc391] | 5 | <para>Those people who have built a <acronym>LFS</acronym> system will be aware
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| 6 | of the general principles of downloading and unpacking software. We will
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[f45b1953] | 7 | however repeat some of that information here for those new to building
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| 8 | their own software.</para>
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| 9 |
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[acfc391] | 10 | <para>Each set of installation instructions contains a <acronym>URL</acronym>
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| 11 | from which you can download the package. We do however keep a selection of
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| 12 | patches available via http. These are referenced as needed in the
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[f45b1953] | 13 | installation instructions.</para>
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| 14 |
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[5e18c49c] | 15 | <para>While you can keep the source <acronym>TAR</acronym> balls anywhere you like, we
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[f45b1953] | 16 | assume that you have unpacked them and unzipped any required patches
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| 17 | into <filename>/usr/src</filename>.</para>
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| 18 |
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[64d97b7c] | 19 | <para>We can not emphasize strongly enough that you should start from a
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[f45b1953] | 20 | <emphasis>clean source tree</emphasis> each time. This means that if
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| 21 | you have had an error, it's usually best to delete the source tree and
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| 22 | re-unpack it <emphasis>before</emphasis> trying again. This obviously
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| 23 | doesn't apply if you're an advanced user used to hacking Makefiles and C
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| 24 | code, but if in doubt, start from a clean tree.</para>
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| 25 |
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| 26 | <sect2>
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| 27 | <title>Unpacking the software</title>
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| 28 |
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| 29 | <para>If a file is tar'ed and gzip'ed, it is unpacked by running one of
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| 30 | the following two commands, depending on the filename:</para>
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| 31 |
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[acfc391] | 32 | <screen><command>tar -xvzf filename.tar.gz
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[75d7f3d7] | 33 | tar -xvzf filename.tgz
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[acfc391] | 34 | tar -xvzf filename.tar.Z</command></screen>
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[f45b1953] | 35 |
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| 36 | <para>If a file is tar'ed and bzip2'ed, it can usually be unpacked by
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| 37 | running:</para>
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| 38 |
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[acfc391] | 39 | <screen><command>tar -jxvf filename.tar.bz2</command></screen>
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[f45b1953] | 40 |
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[acfc391] | 41 | <para>You can also use a slightly different method:</para>
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[f45b1953] | 42 |
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[acfc391] | 43 | <screen><command>bzcat filename.tar.bz2 | tar -xv</command></screen>
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[f45b1953] | 44 |
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| 45 | <para>Finally, you need to be able to unpack patches which are generally
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[5628618e] | 46 | not tar'ed. The best way to do this is to copy the patch file to
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[f45b1953] | 47 | <filename>/usr/src</filename> and then to run one of the following
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| 48 | commands depending on whether the file is .gz or .bz2:</para>
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| 49 |
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[acfc391] | 50 | <screen><command>gunzip patchname.gz
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| 51 | bunzip2 patchname.bz2</command></screen>
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[f45b1953] | 52 |
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| 53 | </sect2>
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| 54 |
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[0c603671] | 55 | <sect2>
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| 56 | <title>Verifying file integrity using md5sum</title>
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| 57 |
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| 58 | <para>Generally, to verify that the downloaded file is genuine and complete,
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| 59 | most package maintainers also distribute md5sums of the files.
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| 60 | To verify the md5sum of the downloaded files, download both the file and the
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| 61 | corresponding md5sum file to the same directory (preferably from different
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| 62 | on-line locations), and (assuming file.md5sum is the md5sum file downloaded)
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| 63 | run the following command:</para>
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| 64 |
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| 65 | <screen><command>md5sum -c file.md5sum</command></screen>
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| 66 |
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| 67 | <para>If there are any errors, they will be reported.</para>
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| 68 |
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| 69 | </sect2>
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| 70 |
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| 71 | <sect2>
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| 72 | <title>Creating Log files during installation</title>
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| 73 |
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| 74 | <para>For larger packages, it is convenient to create log files instead of
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| 75 | staring at the screen hoping to catch a particular error or warning. Log files
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| 76 | are also useful for debugging and keeping records. The following command
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| 77 | allows you to create a installation log. Replace <command> with the
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| 78 | command you intend to execute.</para>
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| 79 |
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| 80 | <screen><command>( <command> 2>&1 | tee compile.log && exit $PIPESTATUS )</command></screen>
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| 81 |
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| 82 | <para><parameter>2>&1</parameter> redirects error messages
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| 83 | to the same location as normal output. The <command>tee</command> command
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| 84 | allows viewing of the output while logging the results to a file. The parentheses
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| 85 | around the command run the entire command in a subshell and finally the
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| 86 | <command>exit $PIPESTATUS</command> ensures the result of the <command>
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| 87 | is returned as the result and not the result of the <command>tee</command> command.</para>
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| 88 |
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| 89 | </sect2>
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| 90 |
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[f45b1953] | 91 | </sect1>
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