Beyond Linux From Scratch: Version 5.0-PRE1
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The Bash Shell Startup Files

The shell program /bin/bash (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 /etc directory generally provide global settings. If an equivalent file exists in your home directory it may override the global settings.

An interactive login shell is started after a successful login, using /bin/login, by reading the /etc/passwd file. An interactive non-login shell is started at the command-line (e.g. [prompt]$/bin/bash). 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 more information see info bash -- Nodes: Bash Startup Files and Interactive Shells.

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

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

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

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

Here is a base /etc/profile. 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 PS1 environment variable) see info bash -- Node: Printing a Prompt.

cat > /etc/profile << "EOF"
# Begin /etc/profile
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# 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="&:[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
EOF

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

cat > /etc/bashrc << "EOF"
# Begin /etc/bashrc 
# Written for Beyond Linux From Scratch 
# by James Robertson <jameswrobertson@earthlink.net>

# 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
EOF

Here is a base ~/.bash_profile. 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 /etc/skel/.bash_profile and check the permissions after the command is run. You can then copy /etc/skel/.bash_profile to the home directories of already existing users, including root, and set the owner and group appropriately. 

cat > ~/.bash_profile << "EOF"
# Begin ~/.bash_profile
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# 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
EOF

Here is a base ~/.bashrc. Comments in the file should explain everything you need. The comments and instructions for using /etc/skel for .bash_profile above also apply here. Only the target file names are different.

cat > ~/.bashrc << "EOF"
# Begin ~/.bashrc
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# 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
EOF

Here is a base ~/.bash_logout. Comments in the file should explain everything you need. You will notice that the base ~/.bash_logout does not include a clear command. This is because the clear is handled in the /etc/issue file.

cat > ~/.bash_logout << "EOF"
# Begin ~/.bash_logout
# Written for Beyond Linux From Scratch
# by James Robertson <jameswrobertson@earthlink.net>

# Personal items to perform on logout.

# End ~/.bash_logout
EOF

If you want to use the dircolors capability then run the following command. The /etc/skel setup steps seen above also can be used here to provide a .dircolors 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.

/bin/dircolors -p > /etc/dircolors

Ian Macdonald has written an excellent collection of tips and tricks to enhance your shell environment. You can read it online at http://www.caliban.org/bash/index.shtml

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