We will be using shell to do most of our work. Shell accepts and runs commands. When you login, few files are read in to set up your environment.
1) .bash_profile and .bashrc
.bash_profile is read first and it calls the second file, .bashrc. This is done every time you log in and it initializes and customizes your environment.
.bash_profile file is where you can customize your environmental variable
below a typical bash profile which also adds a directory bin to your path ($PATH described above).
# ~/.bash_profile: executed by bash(1) for login shells.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package.
# the default umask is set in /etc/login.defs
#umask 022
# include .bashrc if it exists
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
# set PATH so it includes user's private bin if it exists
if [ -d ~/bin ] ; then
PATH=~/bin:"${PATH}"
fi
2) $PATH
a variable $PATH is a set of directories (separated by : ) where the system assumes the executable programs are located.
when you use an executable command in your script, the system will look into your $PATH to identify the executable code.
to check what your path is you can use the following command:
echo $PATH
3) bin
it is a good idea to create a sub-directory bin in your home directory - this is a place to keep any scripts or programs you write,
or to add symlinks to some programs.
You should add bin to your bash profile [it is already done in the example above].