configuration environment bash

We can setup files that automatically configure our working environment every time we login. The three major configuration files for the bash shell are:

/etc/profile - generic system-wide profile
.bash_profile - personal profile that is processed every time you login
.bashrc - setup file processed every time you open a non-login shell

0) in case that the tcsh is used in the env,I first change from tcsh to bash.
which bash ----- produces /bin/bash
setenv SHELL /bin/bash
exec /bin/bash --login

1) in order to show colors for folders in the terminal window:
I added in the .bash_profile
export CLICOLOR=1
export LSCOLORS=ExFxCxDxBxegedabagacad

2) in order that some alias can be used permanently, I add in the .bashrc and .bash_profile the alias that I use. IN this way the alias can be used automatically when I log in each time.

alias ls='ls -l'