source: postlfs/config/profile.xml@ 8bb9b01e

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;
]>

<sect1 id="postlfs-config-profile" xreflabel="The Bash Shell Startup Files">
  <?dbhtml filename="profile.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>The Bash Shell Startup Files</title>

  <para>The shell program <filename>/bin/bash</filename> (hereafter
  referred to as just "the shell") uses a collection of startup files to
  help create an environment.  Each file has a specific use and
  may affect login and interactive environments differently.  The files in
  the <filename class="directory">/etc</filename> directory generally provide
  global settings. If an equivalent file exists in your home directory it may
  override the global settings.</para>

  <para>An interactive login shell is started after a successful login, using
  <filename>/bin/login</filename>, by reading the <filename>/etc/passwd</filename>
  file.  This shell invocation normally reads <filename>/etc/profile</filename>
  and its private equivalent <filename>~/.bash_profile</filename> upon
  startup.</para>

  <para>An interactive non-login shell is normally started at the command-line
  using a shell program (e.g.,
  <prompt>[prompt]$</prompt><command>/bin/bash</command>) or by the
  <command>/bin/su</command> command.  An interactive non-login shell is also
  started with a terminal program such as <command>xterm</command> or
  <command>konsole</command> from within a graphical environment. This type of
  shell invocation normally copies the parent environment and then reads the
  user's <filename>~/.bashrc</filename> file for additional startup configuration
  instructions.</para>

  <para>A non-interactive shell is usually present when a shell script is
  running.  It is non-interactive because it is processing a script and not
  waiting for user input between commands. For these shell invocations, only
  the environment inherited from the parent shell is used.</para>

  <para> The file <filename>~/.bash_logout</filename> is not used for an
  invocation of the shell.  It is read and executed when a user exits from an
  interactive login shell.</para>

  <para>Many distributions use <filename>/etc/bashrc</filename> for system wide
  initialization of non-login shells. This file is usually called from the
  user's <filename>~/.bashrc</filename> file and is not built directly into
  <command>bash</command> itself.  This convention is followed in this
  section.</para>

  <para>For more information see <command>info bash</command> --
  <emphasis role="strong">Nodes: Bash Startup Files and Interactive
  Shells</emphasis>.</para>

  <note>
    <para>Most of the instructions below are used to create files located in
    the <filename class='directory'>/etc</filename> directory structure which
    requires you to execute the commands as the
    <systemitem class='username'>root</systemitem> user. If you elect to create
    the files in user's home directories instead, you should run the commands
    as an unprivileged user.</para>
  </note>

  <sect2 id="etc-profile-profile">
    <title>/etc/profile</title>

    <indexterm zone="postlfs-config-profile etc-profile-profile">
      <primary sortas="e-etc-profile">/etc/profile</primary>
    </indexterm>

    <para>Here is a base <filename>/etc/profile</filename>. This file starts by
    setting up some helper functions and some basic parameters.  It specifies some
    <command>bash</command> history parameters and, for security purposes,
    disables keeping a permanent history file for the <systemitem
    class="username">root</systemitem> user.  It also sets a
    default user prompt.  It then calls small, single purpose scripts in the
    <filename class='directory'>/etc/profile.d</filename> directory to provide most
    of the initialization.</para>

    <para>For more information on the escape sequences you can use for your prompt
    (i.e., the <envar>PS1</envar> environment variable) see <command>info
    bash</command> -- <emphasis role="strong">Node: Printing a
    Prompt</emphasis>.</para>

<screen role="root"><userinput>cat &gt; /etc/profile &lt;&lt; "EOF"
<literal># Begin /etc/profile
# Written for Beyond Linux From Scratch
# by James Robertson &lt;jameswrobertson@earthlink.net&gt;
# modifications by Dagmar d'Surreal &lt;rivyqntzne@pbzpnfg.arg&gt;

# System wide environment variables and startup programs.

# System wide aliases and functions should go in /etc/bashrc.  Personal
# environment variables and startup programs should go into
# ~/.bash_profile.  Personal aliases and functions should go into
# ~/.bashrc.

# Functions to help us manage paths.  Second argument is the name of the
# path variable to be modified (default: PATH)
pathremove () {
        local IFS=':'
        local NEWPATH
        local DIR
        local PATHVARIABLE=${2:-PATH}
        for DIR in ${!PATHVARIABLE} ; do
                if [ "$DIR" != "$1" ] ; then
                  NEWPATH=${NEWPATH:+$NEWPATH:}$DIR
                fi
        done
        export $PATHVARIABLE="$NEWPATH"
}

pathprepend () {
        pathremove $1 $2
        local PATHVARIABLE=${2:-PATH}
        export $PATHVARIABLE="$1${!PATHVARIABLE:+:${!PATHVARIABLE}}"
}

pathappend () {
        pathremove $1 $2
        local PATHVARIABLE=${2:-PATH}
        export $PATHVARIABLE="${!PATHVARIABLE:+${!PATHVARIABLE}:}$1"
}


# Set the initial path
export PATH=/bin:/usr/bin

if [ $EUID -eq 0 ] ; then
        pathappend /sbin:/usr/sbin
        unset HISTFILE
fi

# Setup some environment variables.
export HISTSIZE=1000
export HISTIGNORE="&amp;:[bf]g:exit"
#export PS1="[\u@\h \w]\\$ "
export PS1='\u@\h:\w\$ '

for script in /etc/profile.d/*.sh ; do
        if [ -r $script ] ; then
                . $script
        fi
done

# Now to clean up
unset pathremove pathprepend pathappend

# End /etc/profile</literal>
EOF</userinput></screen>

    <sect3 id="etc-profile.d">
      <title>The /etc/profile.d Directory</title>

      <indexterm zone="postlfs-config-profile etc-profile.d">
        <primary sortas="e-etc-profile.d">/etc/profile.d</primary>
      </indexterm>

      <para>Now create the <filename class='directory'>/etc/profile.d</filename>
      directory, where the individual initialization scripts are placed:</para>

<screen role="root"><userinput>install --directory --mode=0755 --owner=root --group=root /etc/profile.d</userinput></screen>

    </sect3>

    <sect3 id="etc-profile.d-dircolors.sh">
      <title>/etc/profile.d/dircolors.sh</title>

      <indexterm zone="postlfs-config-profile etc-profile.d-dircolors.sh">
        <primary sortas="e-etc-profile.d-dircolors.sh">/etc/profile.d/dircolors.sh</primary>
      </indexterm>

      <para>This script uses the <filename>~/.dircolors</filename> and
      <filename>/etc/dircolors</filename> files to control the colors of file names in a
      directory listing. They control colorized output of things like <command>ls
      --color</command>.  The explanation of how to initialize these files is at the
      end of this section.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/dircolors.sh &lt;&lt; "EOF"
<literal># Setup for /bin/ls to support color, the alias is in /etc/bashrc.
if [ -f "/etc/dircolors" ] ; then
        eval $(dircolors -b /etc/dircolors)

        if [ -f "$HOME/.dircolors" ] ; then
                eval $(dircolors -b $HOME/.dircolors)
        fi
fi
alias ls='ls --color=auto'</literal>
EOF</userinput></screen>

    </sect3>

    <sect3 id="extrapaths.sh">
      <title>/etc/profile.d/extrapaths.sh</title>

      <indexterm zone="postlfs-config-profile extrapaths.sh">
        <primary sortas="e-etc-profile.d-extrapaths.sh">/etc/profile.d/extrapaths.sh</primary>
      </indexterm>

      <para>This script adds several useful paths to the <envar>PATH</envar> and
      <envar>PKG_CONFIG_PATH</envar> environment variables.  If you want, you
      can uncomment the last section to put a dot at the end of your path. This will
      allow executables in the current working directory to be executed without
      specifiying a ./, however you are warned that this is generally considered a
      security hazard.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/extrapaths.sh &lt;&lt; "EOF"
<literal>if [ -d /usr/local/lib/pkgconfig ] ; then
        pathappend /usr/local/lib/pkgconfig PKG_CONFIG_PATH
fi
if [ -d /usr/local/bin ]; then
        pathprepend /usr/local/bin
fi
if [ -d /usr/local/sbin -a $EUID -eq 0 ]; then
        pathprepend /usr/local/sbin
fi

if [ -d ~/bin ]; then
        pathprepend ~/bin
fi
#if [ $EUID -gt 99 ]; then
#        pathappend .
#fi</literal>
EOF</userinput></screen>

    </sect3>

    <sect3 id="readline.sh">
      <title>/etc/profile.d/readline.sh</title>

      <indexterm zone="postlfs-config-profile readline.sh">
        <primary sortas="e-etc-profile.d-readline.sh">/etc/profile.d/readline.sh</primary>
      </indexterm>

      <para>This script sets up the default <filename>inputrc</filename>
      configuration file. If the user does not have individual settings, it uses the
      global file.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/readline.sh &lt;&lt; "EOF"
<literal># Setup the INPUTRC environment variable.
if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ] ; then
        INPUTRC=/etc/inputrc
fi
export INPUTRC</literal>
EOF</userinput></screen>

    </sect3>

    <sect3 id="umask.sh">
      <title>/etc/profile.d/umask.sh</title>

      <indexterm zone="postlfs-config-profile umask.sh">
        <primary sortas="e-etc-profile.d-umask.sh">/etc/profile.d/umask.sh</primary>
      </indexterm>

      <para>Setting the <command>umask</command> value is important for security.
      Here the default group write permissions are turned off for system users and when
      the user name and group name are not the same.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/umask.sh &lt;&lt; "EOF"
<literal># By default we want the umask to get set.
if [ "$(id -gn)" = "$(id -un)" -a $EUID -gt 99 ] ; then
  umask 002
else
  umask 022
fi</literal>
EOF</userinput></screen>

    </sect3>

    <sect3 id="X.sh">
      <title>/etc/profile.d/X.sh</title>

      <indexterm zone="postlfs-config-profile X.sh">
        <primary sortas="e-etc-profile.d-X.sh">/etc/profile.d/X.sh</primary>
      </indexterm>

      <para>If <application>X</application> is installed, the <envar>PATH</envar>
      and <envar>PKG_CONFIG_PATH</envar> variables are also updated.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/X.sh &lt;&lt; "EOF"
<literal>if [ -x /usr/X11R6/bin/X ]; then
        pathappend /usr/X11R6/bin
fi
if [ -d /usr/X11R6/lib/pkgconfig ] ; then
        pathappend /usr/X11R6/lib/pkgconfig PKG_CONFIG_PATH
fi</literal>
EOF</userinput></screen>

    </sect3>

    <sect3 id="extra-prompt.sh">
      <title>/etc/profile.d/extra-prompt.sh</title>

      <indexterm zone="postlfs-config-profile extra-prompt.sh">
        <primary sortas="e-etc-profile.d-prompt.sh">/etc/profile.d/extra-prompt.sh</primary>
      </indexterm>

      <para>This script shows an example of a different way of setting the
      prompt.  The normal variable, <envar>PS1</envar>, is supplemented by
      <envar>PROMPT_COMMAND</envar>. If set, the value of
      <envar>PROMPT_COMMAND</envar> is executed as a command prior to issuing
      each primary prompt.  The sequence \e is an ESC character.  \a is a
      BEL character.  For a reference on <command>xterm</command> escape
      sequences, see <ulink
      url="http://rtfm.etla.org/xterm/ctlseq.html"/>.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/extra-prompt.sh &lt;&lt; "EOF"
<literal>PROMPT_COMMAND='echo -ne "\e[1m${USER}@${HOSTNAME} : ${PWD}\e[0m\a"'
export PROMPT_COMMAND</literal>
EOF</userinput></screen>

    <para>The escape sequences above are BOLD, NORMAL, and BEL.</para>

    </sect3>

    <sect3 id="i18n.sh">
      <title>'/etc/profile.d/i18n.sh'</title>

    <indexterm zone="postlfs-config-profile i18n.sh">
      <primary sortas="e-etc-profile.d-i18n.sh">/etc/profile.d/i18n.sh</primary>
    </indexterm>

      <para>This script sets an environment variable necessary for
      native language support. A full discussion on determining this
      variable can be found on the <ulink
      url="&lfs-root;/chapter07/profile.html">LFS Bash Shell
      Startup Files</ulink> page.</para>

<screen role="root"><userinput>cat &gt; /etc/profile.d/i18n.sh &lt;&lt; "EOF"
<literal># Set up i18n variables
export LANG=<replaceable>&lt;ll&gt;</replaceable>_<replaceable>&lt;CC&gt;</replaceable>.<replaceable>&lt;charmap&gt;</replaceable><replaceable>&lt;@modifiers&gt;</replaceable></literal>
EOF</userinput></screen>

    </sect3>

    <sect3>
      <title>Other Initialization Values</title>

      <para>Other initialization can easily be added to the
      <filename>profile</filename> by adding additional scripts to the
      <filename class='directory'>/etc/profile.d</filename> directory.</para>

    </sect3>

  </sect2>

  <sect2 id="etc-bashrc-profile">
    <title>/etc/bashrc</title>

    <indexterm zone="postlfs-config-profile etc-bashrc-profile">
      <primary sortas="e-etc-bashrc">/etc/bashrc</primary>
    </indexterm>

    <para>Here is a base <filename>/etc/bashrc</filename>.  Comments in the
    file should explain everything you need.</para>

<screen role="root"><userinput>cat &gt; /etc/bashrc &lt;&lt; "EOF"
<literal># Begin /etc/bashrc
# Written for Beyond Linux From Scratch
# by James Robertson &lt;jameswrobertson@earthlink.net&gt;
# updated by Bruce Dubbs &lt;bdubbs@&lfs-domainname;&gt;

# System wide aliases and functions.

# System wide environment variables and startup programs should go into
# /etc/profile.  Personal environment variables and startup programs
# should go into ~/.bash_profile.  Personal aliases and functions should
# go into ~/.bashrc

# Provides a colored /bin/ls command.  Used in conjunction with code in
# /etc/profile.

alias ls='ls --color=auto'

# Provides prompt for non-login shells, specifically shells started
# in the X environment. [Review the LFS archive thread titled
# PS1 Environment Variable for a great case study behind this script
# addendum.]

#export PS1="[\u@\h \w]\\$ "
export PS1='\u@\h:\w\$ '

# End /etc/bashrc</literal>
EOF</userinput></screen>

  </sect2>

  <sect2 id="bash_profile-profile">
    <title>~/.bash_profile</title>

    <indexterm zone="postlfs-config-profile bash_profile-profile">
      <primary sortas="e-AA.bash_profile">~/.bash_profile</primary>
    </indexterm>

    <para>Here is a base <filename>~/.bash_profile</filename>.  If you want each
    new user to have this file automatically, just change the output of
    the command to <filename>/etc/skel/.bash_profile</filename> and check the
    permissions after the command is run. You can then copy
    <filename>/etc/skel/.bash_profile</filename> to the home directories of already
    existing users, including <systemitem class="username">root</systemitem>,
    and set the owner and group appropriately.</para>

<screen><userinput>cat &gt; ~/.bash_profile &lt;&lt; "EOF"
<literal># Begin ~/.bash_profile
# Written for Beyond Linux From Scratch
# by James Robertson &lt;jameswrobertson@earthlink.net&gt;
# updated by Bruce Dubbs &lt;bdubbs@&lfs-domainname;&gt;

# Personal environment variables and startup programs.

# Personal aliases and functions should go in ~/.bashrc.  System wide
# environment variables and startup programs are in /etc/profile.
# System wide aliases and functions are in /etc/bashrc.

append () {
  # First remove the directory
  local IFS=':'
  local NEWPATH
  for DIR in $PATH; do
     if [ "$DIR" != "$1" ]; then
       NEWPATH=${NEWPATH:+$NEWPATH:}$DIR
     fi
  done

  # Then append the directory
  export PATH=$NEWPATH:$1
}

if [ -f "$HOME/.bashrc" ] ; then
  source $HOME/.bashrc
fi

if [ -d "$HOME/bin" ] ; then
  append $HOME/bin
fi

unset append

# End ~/.bash_profile</literal>
EOF</userinput></screen>

  </sect2>

  <sect2 id="bashrc-profile">
    <title>~/.bashrc</title>

    <indexterm zone="postlfs-config-profile bashrc-profile">
      <primary sortas="e-AA.bashrc">~/.bashrc</primary>
    </indexterm>

    <para>Here is a base <filename>~/.bashrc</filename>.  The comments and
    instructions for using <filename class="directory">/etc/skel</filename> for
    <filename>.bash_profile</filename> above also apply here. Only the target file
    names are different.</para>

<screen><userinput>cat &gt; ~/.bashrc &lt;&lt; "EOF"
<literal># Begin ~/.bashrc
# Written for Beyond Linux From Scratch
# by James Robertson &lt;jameswrobertson@earthlink.net&gt;

# Personal aliases and functions.

# Personal environment variables and startup programs should go in
# ~/.bash_profile.  System wide environment variables and startup
# programs are in /etc/profile.  System wide aliases and functions are
# in /etc/bashrc.

if [ -f "/etc/bashrc" ] ; then
  source /etc/bashrc
fi

# End ~/.bashrc</literal>
EOF</userinput></screen>

  </sect2>


  <sect2 id="bash_logout-profile">
    <title>~/.bash_logout</title>

    <indexterm zone="postlfs-config-profile bash_logout-profile">
      <primary sortas="e-AA.bash_logout">~/.bash_logout</primary>
    </indexterm>

    <para>This is an empty <filename>~/.bash_logout</filename> that can be used as
    a template.  You will notice that the base <filename>~/.bash_logout</filename>
    does not include a <userinput>clear</userinput> command.  This is because the
    clear is handled in the <filename>/etc/issue</filename> file.</para>

<screen><userinput>cat &gt; ~/.bash_logout &lt;&lt; "EOF"
<literal># Begin ~/.bash_logout
# Written for Beyond Linux From Scratch
# by James Robertson &lt;jameswrobertson@earthlink.net&gt;

# Personal items to perform on logout.

# End ~/.bash_logout</literal>
EOF</userinput></screen>

  </sect2>


  <sect2 id="etc-dircolors-profile">
    <title>/etc/dircolors</title>

    <indexterm zone="postlfs-config-profile etc-dircolors-profile">
      <primary sortas="e-etc-dircolors">/etc/dircolors</primary>
    </indexterm>

    <indexterm zone="postlfs-config-profile etc-dircolors-profile">
      <primary sortas="e-AA.dircolors">~/.dircolors</primary>
    </indexterm>

    <para> If you want to use the <filename>dircolors</filename> capability, then
    run the following command. The <filename class="directory">/etc/skel</filename>
    setup steps shown above also can be used here to provide a
    <filename>~/.dircolors</filename> file when a new user is set up. As before,
    just change the output file name on the following command and assure the
    permissions, owner, and group are correct on the files created and/or
    copied.</para>

<screen role="root"><userinput>dircolors -p > /etc/dircolors</userinput></screen>

    <para>If you wish to customize the colors used for different file types, you can
    edit the <filename>/etc/dircolors</filename> file.  The instructions for setting
    the colors are embedded in the file.</para>


    <para>Finally, Ian Macdonald has written an excellent collection of tips and
    tricks to enhance your shell environment.  You can read it online at
    <ulink url="http://www.caliban.org/bash/index.shtml"/>.</para>

  </sect2>

</sect1>