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. 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. This shell invocation normally reads /etc/profile and its private equivalent ~/.bash_profile upon startup.
An interactive non-login shell is normally started at the command-line using a shell program (e.g.,[prompt]$/bin/bash) or by the /bin/su command. An interactive non-login shell is also started with a terminal program such as xterm or konsole from within a graphical environment. This type of shell invocation normally copies the parent environment and then reads the user's ~/.bashrc file for additional startup configuration instructions.
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.
The file ~/.bash_logout is not used for an invocation of the shell. It is read and executed when a user exits from an interactive login shell.
Many distributions use /etc/bashrc for system wide initialization of non-login shells. This file is usually called from the user's ~/.bashrc file and is not built directly into bash itself. This convention is followed in this section.
For more information see info bash -- Nodes: Bash Startup Files and Interactive Shells.
![[Note]](http://www.linuxfromscratch.org/blfs/view/svn/images/note.png)
Note
Most of the instructions below are used to create files located in the /etc directory structure which requires you to execute the commands as the root user. If you elect to create the files in user's home directories instead, you should run the commands as an unprivileged user.
/etc/profile
Here is a base /etc/profile. This file starts by setting up some helper functions and some basic parameters. It specifies some bash history parameters and, for security purposes, disables keeping a permanent history file for theroot user. It also sets a default user prompt. It then calls small, single purpose scripts in the /etc/profile.ddirectory to provide most of the initialization.
For more information on the escape sequences you can use for your prompt (i.e., 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 # modifications by Dagmar d'Surreal # 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="&:[bf]g:exit" # Setup a red prompt for root and a green one for users. NORMAL="\[\e[0m\]" RED="\[\e[1;31m\]" GREEN="\[\e[1;32m\]" if [[ $EUID == 0 ]] ; then PS1="$RED\u [ $NORMAL\w$RED ]# $NORMAL" else PS1="$GREEN\u [ $NORMAL\w$GREEN ]\$ $NORMAL" fi 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 EOFThe /etc/profile.d Directory
Now create the /etc/profile.d directory, where the individual initialization scripts are placed:
install --directory --mode=0755 --owner=root --group=root /etc/profile.d
/etc/profile.d/dircolors.sh
This script uses the ~/.dircolors and /etc/dircolors files to control the colors of file names in a directory listing. They control colorized output of things like ls --color. The explanation of how to initialize these files is at the end of this section.
cat > /etc/profile.d/dircolors.sh << "EOF" # 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' EOF/etc/profile.d/extrapaths.sh
This script adds several useful paths to the PATH and PKG_CONFIG_PATH 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.
cat > /etc/profile.d/extrapaths.sh << "EOF" 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 [ $EUID -gt 99 ]; then # pathappend . #fi EOF/etc/profile.d/readline.sh
This script sets up the default inputrc configuration file. If the user does not have individual settings, it uses the global file.
cat > /etc/profile.d/readline.sh << "EOF" # Setup the INPUTRC environment variable. if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ] ; then INPUTRC=/etc/inputrc fi export INPUTRC EOF/etc/profile.d/umask.sh
Setting the umask value is important for security. Here the default group write permissions are turned off for system users and when the user name and group name are not the same.
cat > /etc/profile.d/umask.sh << "EOF" # By default we want the umask to get set. if [ "$(id -gn)" = "$(id -un)" -a $EUID -gt 99 ] ; then umask 002 else umask 022 fi EOF/etc/profile.d/X.sh
If X is installed, the PATH and PKG_CONFIG_PATH variables are also updated.
cat > /etc/profile.d/X.sh << "EOF" 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 EOF/etc/profile.d/i18n.sh
This script sets an environment variable necessary for native language support. A full discussion on determining this variable can be found on the LFS Bash Shell Startup Files page.
cat > /etc/profile.d/i18n.sh << "EOF" # Set up i18n variables export LANG=<@modifiers> EOFOther Initialization Values
Other initialization can easily be added to the profile by adding additional scripts to the /etc/profile.d directory.
/etc/bashrc
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 # updated by Bruce Dubbs # 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.] NORMAL="\[\e[0m\]" RED="\[\e[1;31m\]" GREEN="\[\e[1;32m\]" if [[ $EUID == 0 ]] ; then PS1="$RED\u [ $NORMAL\w$RED ]# $NORMAL" else PS1="$GREEN\u [ $NORMAL\w$GREEN ]\$ $NORMAL" fi # End /etc/bashrc EOF~/.bash_profile
Here is a base ~/.bash_profile. If you want each new user to have this file automatically, just change the output of the 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 # updated by Bruce Dubbs # 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 EOF~/.bashrc
Here is a base ~/.bashrc. 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 # 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~/.bash_logout
This is an empty ~/.bash_logout that can be used as a template. 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 # Personal items to perform on logout. # End ~/.bash_logout EOF/etc/dircolors
If you want to use the dircolors capability, then run the following command. The /etc/skel setup steps shown 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.
dircolors -p > /etc/dircolors
If you wish to customize the colors used for different file types, you can edit the /etc/dircolors file. The instructions for setting the colors are embedded in the file.
Finally, 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.
Last updated on 2008-05-09 08:00:42 -0500
Reference: Directly Copy From http://www.linuxfromscratch.org/blfs/view/svn/postlfs/profile.html
