# source
# Execute commands from a file in the current shell

# This is a shell built-in, available within most if not all shells. However, -
# it may only be available as `.` in some older shells, such as Bourne shell.
# Its first argument is a file, with all proceeding arguments being parameters
# to the aforementioned file.

# Run shell code residing within FILE as though you'd entered it in yourself.
source FILE
# The above can be written in short-hand, for the same effect, shell allowing.
. FILE

#  Source FILE with the given arguments to said file.
source FILE Argument_1 Argument_2 Argument_3 ...