1 | <sect1 id="postlfs-config-profile" xreflabel="The Bash Shell Startup Files">
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2 | <?dbhtml filename="profile.html" dir="postlfs"?>
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3 | <title>The Bash Shell Startup Files</title>
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4 |
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5 | <para>The shell program <filename>/bin/bash</filename> (hereafter
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6 | referred to as just "the shell") uses a collection of startup files to
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7 | help create an environment to run in. Each file has a specific use and
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8 | may affect login and interactive environments differently. The files in
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9 | the <filename class="directory">/etc</filename> directory generally provide global
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10 | settings. If an equivalent file exists in your home directory it may
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11 | override the global settings.
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12 | </para>
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13 |
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14 | <para>An interactive login shell is started after a successful login, using
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15 | <filename>/bin/login</filename>, by reading the
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16 | <filename>/etc/passwd</filename> file. An
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17 | interactive non-login shell is started at the command-line (e.g.
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18 | <prompt>[prompt]$</prompt><command>/bin/bash</command>). A non-interactive
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19 | shell is usually present when a shell script is running. It is non-interactive
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20 | because it is processing a script and not waiting for user input between
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21 | commands.</para>
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22 |
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23 | <para>For more information see <command>info bash</command> --
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24 | <emphasis role="strong">Nodes: Bash Startup Files and Interactive
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25 | Shells.</emphasis></para>
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26 |
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27 | <para>The following files are used to make sure that the correct
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28 | environment is established for each of the ways the shell can be invoked:
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29 | <filename>/etc/profile</filename> and its private equivalent
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30 | <filename>~/.bash_profile</filename>, and
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31 | <filename>/etc/bashrc</filename> (unofficial) and its private equivalent
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32 | <filename>~/.bashrc</filename>.
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33 | </para>
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34 |
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35 | <para>
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36 | The file <filename>~/.bash_logout</filename> is not used for an
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37 | invocation of the shell. It is read by the shell when a user logs out
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38 | of the system.</para>
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39 |
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40 | <para>The files <filename>/etc/profile</filename> and
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41 | <filename>~/.bash_profile</filename> are read when the shell is invoked
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42 | as an interactive login shell. The file <filename>~/.bashrc</filename>
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43 | is read when the shell is invoked as an interactive non-login
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44 | shell and it reads <filename>/etc/bashrc</filename> if it exists</para>
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45 |
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46 | <para>Also useful are the <filename>/etc/dircolors</filename> and
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47 | <filename>~/.dircolors</filename> files called from
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48 | <filename>/etc/profile</filename>. They control colorized output of
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49 | things like <command>ls --color</command>.
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50 | </para>
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51 |
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52 | <para>Here is a base <filename>/etc/profile</filename>. Comments in the
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53 | file should explain everything you need. For more information on the
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54 | escape sequences you can use for your prompt (e.g. the
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55 | <envar>PS1</envar> environment variable) see <command>info
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56 | bash</command> -- <emphasis role="strong">Node: Printing a
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57 | Prompt.</emphasis></para>
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58 |
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59 | <screen><userinput><command>cat > /etc/profile << "EOF"</command>
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60 | # Begin /etc/profile
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61 | # Written for Beyond Linux From Scratch
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62 | # by James Robertson <jameswrobertson@earthlink.net>
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63 |
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64 | # System wide environment variables and startup programs.
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65 |
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66 | # System wide aliases and functions should go in /etc/bashrc. Personal
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67 | # environment variables and startup programs should go into
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68 | # ~/.bash_profile. Personal aliases and functions should go into
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69 | # ~/.bashrc.
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70 |
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71 | # Function to help us manage paths
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72 | pathman () {
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73 | if ! echo $PATH | /bin/egrep -q "(^|:)$1($|:)" ; then
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74 | if [ "$2" = "last" ] ; then
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75 | PATH=$PATH:$1
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76 | else
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77 | PATH=$1:$PATH
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78 | fi
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79 | fi
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80 | }
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81 |
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82 | # Add to the standard path.
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83 | if [ $(id -u) = 0 ] ; then
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84 | if [ -d "/usr/local/sbin" ] ; then
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85 | pathman /usr/local/sbin last
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86 | fi
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87 | fi
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88 |
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89 | if [ $(id -u) != 0 ] ; then
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90 | if [ -d "/usr/local/bin" ] ; then
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91 | pathman /usr/local/bin last
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92 | fi
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93 | fi
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94 |
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95 | if [ -d "/usr/X11R6/bin" ] ; then
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96 | pathman /usr/X11R6/bin last
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97 | fi
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98 |
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99 | # Setup some environment variables.
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100 | HISTSIZE=1000
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101 | HISTIGNORE="&:[bf]g:exit"
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102 | PS1="[\u@\h \w]\\$ "
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103 |
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104 | # Setup the INPUTRC environment variable.
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105 | if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ] ; then
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106 | INPUTRC=/etc/inputrc
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107 | fi
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108 |
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109 | # Setup for /bin/ls to support color, the alias is in /etc/bashrc.
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110 | if [ -f "/etc/dircolors" ] ; then
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111 | eval $(dircolors -b /etc/dircolors)
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112 |
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113 | if [ -f "$HOME/.dircolors" ] ; then
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114 | eval $(dircolors -b $HOME/.dircolors)
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115 | fi
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116 | fi
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117 |
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118 | export PATH HISTSIZE HISTIGNORE PS1 LS_COLORS INPUTRC
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119 |
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120 | # End /etc/profile
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121 | <command>EOF</command></userinput></screen>
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122 |
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123 | <para>Here is a base <filename>/etc/bashrc</filename>. Comments in the
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124 | file should explain everything you need.</para>
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125 |
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126 | <screen><userinput><command>cat > /etc/bashrc << "EOF"</command>
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127 | # Begin /etc/bashrc
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128 | # Written for Beyond Linux From Scratch
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129 | # by James Robertson <jameswrobertson@earthlink.net>
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130 |
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131 | # System wide aliases and functions.
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132 |
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133 | # System wide environment variables and startup programs should go into
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134 | # /etc/profile. Personal environment variables and startup programs
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135 | # should go into ~/.bash_profile. Personal aliases and functions should
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136 | # go into ~/.bashrc
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137 |
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138 | # By default we want the umask to get set.
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139 | # Even for non-interactive and non-login shells.
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140 | if [ "$(id -gn)" = "$(id -un)" -a $(id -u) -gt 99 ] ; then
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141 | umask 002
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142 | else
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143 | umask 022
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144 | fi
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145 |
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146 | # Provides a colored /bin/ls command. Used in conjunction with code in
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147 | # /etc/profile.
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148 | alias ls='ls --color=auto'
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149 |
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150 | # Provides prompt for non-interactive shells, specifically shells started
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151 | # in the xfree environment. [Review archive thread titled PS1
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152 | # Environment Variable for a great case study behind this script
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153 | # addendum.]
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154 | export PS1="[\u@\h \w]\\$ "
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155 |
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156 | # End /etc/bashrc
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157 | <command>EOF</command></userinput></screen>
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158 |
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159 | <para>Here is a base <filename>~/.bash_profile</filename>. Comments in
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160 | the file should explain everything you need. If you want each new user
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161 | to have this file automatically provided, just change the output of the
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162 | next command to <filename>/etc/skel/.bash_profile</filename> and check the
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163 | permissions after the command is run. You can then copy
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164 | <filename>/etc/skel/.bash_profile</filename> to the home directories of
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165 | already existing users, including root, and set the owner and group
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166 | appropriately.
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167 | </para>
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168 |
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169 | <screen><userinput><command>cat > ~/.bash_profile << "EOF"</command>
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170 | # Begin ~/.bash_profile
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171 | # Written for Beyond Linux From Scratch
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172 | # by James Robertson <jameswrobertson@earthlink.net>
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173 |
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174 | # Personal environment variables and startup programs.
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175 |
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176 | # Personal aliases and functions should go in ~/.bashrc. System wide
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177 | # environment variables and startup programs are in /etc/profile.
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178 | # System wide aliases and functions are in /etc/bashrc.
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179 |
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180 | if [ -f "$HOME/.bashrc" ] ; then
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181 | source $HOME/.bashrc
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182 | fi
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183 |
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184 | if [ -d "$HOME/bin" ] ; then
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185 | pathman $HOME/bin last
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186 | fi
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187 |
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188 | export PATH
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189 |
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190 | # End ~/.bash_profile
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191 | <command>EOF</command></userinput></screen>
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192 |
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193 | <para>Here is a base <filename>~/.bashrc</filename>. Comments in the
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194 | file should explain everything you need. The comments and
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195 | instructions for using <filename class="directory">/etc/skel</filename> for
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196 | <filename>.bash_profile</filename> above also apply here. Only the
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197 | target file names are different.</para>
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198 |
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199 | <screen><userinput><command>cat > ~/.bashrc << "EOF"</command>
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200 | # Begin ~/.bashrc
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201 | # Written for Beyond Linux From Scratch
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202 | # by James Robertson <jameswrobertson@earthlink.net>
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203 |
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204 | # Personal aliases and functions.
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205 |
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206 | # Personal environment variables and startup programs should go in
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207 | # ~/.bash_profile. System wide environment variables and startup
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208 | # programs are in /etc/profile. System wide aliases and functions are
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209 | # in /etc/bashrc.
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210 |
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211 | if [ -f "/etc/bashrc" ] ; then
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212 | source /etc/bashrc
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213 | fi
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214 |
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215 | # End ~/.bashrc
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216 | <command>EOF</command></userinput></screen>
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217 |
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218 | <para>Here is a base <filename>~/.bash_logout</filename>. Comments in
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219 | the file should explain everything you need. You will notice that the
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220 | base <filename>~/.bash_logout</filename> does not include a
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221 | <userinput>clear</userinput> command. This is because the clear is
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222 | handled in the <filename>/etc/issue</filename> file.</para>
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223 |
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224 | <screen><userinput><command>cat > ~/.bash_logout << "EOF"</command>
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225 | # Begin ~/.bash_logout
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226 | # Written for Beyond Linux From Scratch
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227 | # by James Robertson <jameswrobertson@earthlink.net>
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228 |
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229 | # Personal items to perform on logout.
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230 |
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231 | # End ~/.bash_logout
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232 | <command>EOF</command></userinput></screen>
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233 |
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234 | <para>
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235 | If you want to use the <filename>dircolors</filename> capability
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236 | then run the following command. The <filename class="directory">/etc/skel</filename> setup
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237 | steps seen above also can be used here to provide a
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238 | <filename>.dircolors</filename> file when a new user is set up. As
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239 | before, just change the output file name on the following command and
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240 | assure the permissions, owner and group are correct on the files created
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241 | and/or copied.
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242 | </para>
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243 |
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244 | <para>
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245 | <userinput><command>/bin/dircolors -p > /etc/dircolors</command></userinput>
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246 | </para>
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247 |
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248 | <para>Ian Macdonald has written an excellent collection of tips and
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249 | tricks to enhance your shell environment. You can read it online at
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250 | <ulink
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251 | url="http://www.caliban.org/bash/index.shtml">http://www.caliban.org/bash/index.shtml</ulink></para>
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252 |
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253 | </sect1>
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