source is a built-in command that executes a script with the namespace scope of the caller.
The point . is an alias.
It will:
The return status is the status of the last command exited within the script (0 if no commands are executed), and false if filename is not found or cannot be read.
source .bash_profile
is the same as
. .bash_profile
. filename [arguments]
source filename [arguments]
where:
If the sourcepath option to the shopt builtin command is turned off, the PATH is not searched.