1 | <?xml version="1.0" encoding="UTF-8"?>
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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4 | <!ENTITY % general-entities SYSTEM "../../general.ent">
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5 | %general-entities;
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6 | ]>
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7 |
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8 | <sect1 id="postlfs-config-skel" xreflabel="Configuring for Adding Users">
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9 | <?dbhtml filename="skel.html"?>
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10 |
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11 |
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12 | <title>Configuring for Adding Users</title>
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13 |
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14 | <indexterm zone="postlfs-config-skel">
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15 | <primary sortas="e-etc-skel">/etc/skel/*</primary>
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16 | </indexterm>
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17 |
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18 | <indexterm zone="postlfs-config-skel">
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19 | <primary sortas="e-etc-default-useradd">/etc/default/useradd</primary>
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20 | </indexterm>
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21 |
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22 | <para>
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23 | Together, the <command>/usr/sbin/useradd</command> command and <filename
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24 | class="directory">/etc/skel</filename> directory (both are easy to
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25 | set up and use) provide a way to assure new users are added to your LFS
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26 | system with the same beginning settings for things such as the
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27 | <envar>PATH</envar>, keyboard processing and other environmental variables.
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28 | Using these two facilities makes it easier to assure this initial state for
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29 | each new user added to the system.
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30 | </para>
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31 |
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32 | <para>
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33 | The <filename class="directory">/etc/skel</filename> directory holds
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34 | copies of various initialization and other files that may be copied to the
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35 | new user's home directory when the <command>/usr/sbin/useradd</command>
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36 | program adds the new user.
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37 | </para>
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38 |
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39 | <bridgehead renderas="sect5">Useradd</bridgehead>
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40 |
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41 | <para>
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42 | The <command>useradd</command> program uses a collection of default
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43 | values kept in <filename>/etc/default/useradd</filename>. This file
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44 | is created in a base LFS installation by the
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45 | <application>Shadow</application> package. If it has been removed or
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46 | renamed, the <command>useradd</command> program uses some internal
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47 | defaults. You can see the default values by running
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48 | <command>/usr/sbin/useradd -D</command>.
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49 | </para>
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50 |
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51 | <para>
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52 | To change these values, simply modify the
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53 | <filename>/etc/default/useradd</filename> file as the
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54 | <systemitem class='username'>root</systemitem> user. An alternative to
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55 | directly modifying the file is to run <command>useradd</command> as the
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56 | <systemitem class='username'>root</systemitem> user while supplying the
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57 | desired modifications on the command line. Information on how to do this
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58 | can be found in the <command>useradd</command> man page.
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59 | </para>
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60 |
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61 | <bridgehead renderas="sect5">/etc/skel</bridgehead>
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62 |
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63 | <para>
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64 | To get started, create an
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65 | <filename class="directory">/etc/skel</filename> directory and make sure it
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66 | is writable only by the system administrator, usually
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67 | <systemitem class="username">root</systemitem>. Creating the directory as
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68 | <systemitem class="username">root</systemitem> is the best way to go.
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69 | </para>
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70 |
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71 | <para>
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72 | The mode of any files from this part of the book that you put in <filename
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73 | class="directory">/etc/skel</filename> should be writable only by the
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74 | owner. Also, since there is no telling what kind of sensitive information
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75 | a user may eventually place in their copy of these files, you should
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76 | make them unreadable by "group" and "other".
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77 | </para>
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78 |
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79 | <para>
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80 | You can also put other files in
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81 | <filename class="directory">/etc/skel</filename> and
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82 | different permissions may be needed for them.
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83 | </para>
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84 |
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85 | <para>
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86 | Decide which initialization files should be provided in every (or most)
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87 | new user's home directory. The decisions you make will affect what you
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88 | do in the next two sections, <xref linkend="postlfs-config-profile"/> and
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89 | <xref linkend="postlfs-config-vimrc"/>. Some or all of those files will be
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90 | useful for <systemitem class="username">root</systemitem>, any
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91 | already-existing users, and new users.
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92 | </para>
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93 |
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94 | <para>
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95 | The files from those sections that you might want to place in
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96 | <filename class="directory">/etc/skel</filename> include
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97 | <filename>.inputrc</filename>, <filename>.bash_profile</filename>,
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98 | <filename>.bashrc</filename>, <filename>.bash_logout</filename>,
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99 | <filename>.dircolors</filename>, and <filename>.vimrc</filename>. If
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100 | you are unsure which of these should be placed there, just continue to
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101 | the following sections, read each section and any references provided,
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102 | and then make your decision.
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103 | </para>
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104 |
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105 | <para>
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106 | You will run a slightly modified set of commands for files which are
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107 | placed in <filename class="directory">/etc/skel</filename>. Each section
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108 | will remind you of this. In brief, the book's commands have been written
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109 | for files <emphasis>not</emphasis> added to <filename class="directory">
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110 | /etc/skel</filename> and instead just sends the results to the user's
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111 | home directory. If the file is going to be in <filename class="directory">
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112 | /etc/skel</filename>, change the book's command(s) to send output there
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113 | instead and then just copy the file from <filename class="directory">
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114 | /etc/skel</filename> to the appropriate directories, like <filename
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115 | class="directory">/etc</filename>, <filename class="directory">~
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116 | </filename> or the home directory of any other user already in the system.
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117 | </para>
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118 |
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119 | <bridgehead renderas="sect5">When Adding a User</bridgehead>
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120 |
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121 | <para>
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122 | When adding a new user with <command>useradd</command>, use
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123 | the <option>-m</option> parameter, which tells
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124 | <command>useradd</command> to create the user's home directory and
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125 | copy files from <filename class="directory">/etc/skel</filename> (can be
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126 | overridden) to the new user's home directory. For example (perform as the
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127 | <systemitem class="username">root</systemitem> user):
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128 | </para>
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129 |
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130 | <screen role="root"><userinput>useradd -m <replaceable><newuser></replaceable></userinput></screen>
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131 |
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132 | <para>
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133 | If you are sharing a <filename class="directory">/home</filename>
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134 | or <filename class="directory">/usr/src</filename> with another
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135 | Linux distro (for example, the host distro used for building LFS), you
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136 | can create a user with the same UID (and, same primary group GID) to
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137 | keep the file ownership consistent across the systems. First, on
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138 | <emphasis>the other distro</emphasis>, get the UID of the user and the
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139 | GID of the user's primary group:
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140 | </para>
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141 |
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142 | <screen role="nodump"><userinput>getent passwd <replaceable><username></replaceable> | cut -d ':' -f 3,4</userinput></screen>
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143 |
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144 | <para>
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145 | The command should output the UID and GID, separated by a colon. Now
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146 | on the BLFS system, create the primary group and the user:
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147 | </para>
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148 |
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149 | <screen role="root"><userinput>groupadd -g <replaceable><GID></replaceable> <replaceable><username></replaceable> &&
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150 | useradd -u <replaceable><UID></replaceable> -g <replaceable><username></replaceable> <replaceable><username></replaceable></userinput></screen>
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151 |
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152 | </sect1>
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