source: postlfs/config/profile.xml@ bae6e15

<sect1 id="postlfs-config-profile" xreflabel="The Bash Shell Startup Files">
<?dbhtml filename="profile.html"?>
<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 to run in.  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.  An
interactive non-login shell is started at the command-line (e.g.
<prompt>[prompt]$</prompt><command>/bin/bash</command>).  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.</para>

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

<para>The following files are used to make sure that the correct
environment is established for each of the ways the shell can be invoked:
<filename>/etc/profile</filename> and its private equivalent
<filename>~/.bash_profile</filename>, and
<filename>/etc/bashrc</filename> (unofficial) and its private equivalent
<filename>~/.bashrc</filename>.
</para>

<para>
The file <filename>~/.bash_logout</filename> is not used for an
invocation of the shell.  It is read by the shell when a user logs out
of the system.</para>

<para>The files <filename>/etc/profile</filename> and
<filename>~/.bash_profile</filename> are read when the shell is invoked
as an interactive login shell.  The file <filename>~/.bashrc</filename>
is read when the shell is invoked as an interactive non-login
shell and it reads <filename>/etc/bashrc</filename> if it exists</para> 

<para>Also useful are the <filename>/etc/dircolors</filename> and
<filename>~/.dircolors</filename> files called from
<filename>/etc/profile</filename>. They control colorized output of
things like <command>ls --color</command>.
</para>

<para>Here is a base <filename>/etc/profile</filename>.  Comments in the
file should explain everything you need.  For more information on the
escape sequences you can use for your prompt (e.g.  the
<envar>PS1</envar> environment variable) see <command>info
bash</command> -- <emphasis role="strong">Node: Printing a
Prompt.</emphasis></para>

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

# Function to help us manage paths
pathman () {
        if ! echo $PATH | /bin/egrep -q "(^|:)$1($|:)" ; then
                if [ "$2" = "last" ] ; then
                        PATH=$PATH:$1
                else
                        PATH=$1:$PATH
                fi
        fi
}

# Add to the standard path.
if [ $(id -u) = 0 ] ; then
        if [ -d "/usr/local/sbin" ] ; then
                pathman /usr/local/sbin last
        fi
fi

if [ $(id -u) != 0 ] ; then
        if [ -d "/usr/local/bin" ] ; then
                pathman /usr/local/bin last
        fi
fi

if [ -d "/usr/X11R6/bin" ] ; then
        pathman /usr/X11R6/bin last
fi

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

# Setup the INPUTRC environment variable.
if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ] ; then
        INPUTRC=/etc/inputrc
fi

# 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

export PATH HISTSIZE HISTIGNORE PS1 LS_COLORS INPUTRC

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

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

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

# By default we want the umask to get set.
# Even for non-interactive and non-login shells.
if [ "$(id -gn)" = "$(id -un)" -a $(id -u) -gt 99 ] ; then
        umask 002
else
        umask 022
fi

# Provides a colored /bin/ls command.  Used in conjunction with code in
# /etc/profile.
alias ls='ls --color=auto'

# Provides prompt for non-interactive shells, specifically shells started
# in the xfree environment. [Review archive thread titled PS1
# Environment Variable for a great case study behind this script
# addendum.]
export PS1="[\u@\h \w]\\$ "

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

<para>Here is a base <filename>~/.bash_profile</filename>.  Comments in
the file should explain everything you need.  If you want each new user
to have this file automatically provided, just change the output of the
next 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 root, and set the owner and group
appropriately. 
</para>

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

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

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

export PATH 

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

<para>Here is a base <filename>~/.bashrc</filename>.  Comments in the
file should explain everything you need.  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><command>cat &gt; ~/.bashrc &lt;&lt; "EOF"</command>
# 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
<command>EOF</command></userinput></screen>

<para>Here is a base <filename>~/.bash_logout</filename>.  Comments in
the file should explain everything you need.  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><command>cat &gt; ~/.bash_logout &lt;&lt; "EOF"</command>
# 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
<command>EOF</command></userinput></screen>

<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 seen 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>

<para>
<userinput><command>dircolors -p > /etc/dircolors</command></userinput>
</para>

<para>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">http://www.caliban.org/bash/index.shtml</ulink></para>

</sect1>