Originally Posted by xeechou
if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
It means if there is a file called .bashrc in user's home folder, then source it.
source it - means run commands in that script, but instead creating a new subshell, execute them in present shell. so whatever you have set in script are now available to current shell (something like logout-login or refresh).
-f = if file exists
. = sourcing (you can also use 'source' instead of '.' both are same)