bashrc location and customization Mac os x

for Lion 10.7.2, the bashrc file located at /etc/

here is my bashrc file:


# System-wide .bashrc file for interactive bash(1) shells.
if [ -z "$PS1" ]; then
   return
fi

PS1='\W\$' #'\h:\W \u\$ '
# Make bash check its window size after a process completes
shopt -s checkwinsize
# Tell the terminal about the working directory at each prompt.
if [ "$TERM_PROGRAM" == "Apple_Terminal" ] && [ -z "$INSIDE_EMACS" ]; then
    update_terminal_cwd() {
        # Identify the directory using a "file:" scheme URL,
        # including the host name to disambiguate local vs.
        # remote connections. Percent-escape spaces.
        local SEARCH=' '
        local REPLACE='%20'
        local PWD_URL="file://$HOSTNAME${PWD//$SEARCH/$REPLACE}"
        printf '\e]7;%s\a' "$PWD_URL"
    }
    PROMPT_COMMAND="update_terminal_cwd; $PROMPT_COMMAND"
fi

export G4WORKDIR=/Applications/g4work
export DYLD_LIBRARY_PATH=/Applications/CLHEP/lib
source /Applications/geant4/geant4.9.4.p03/env.sh