This may sounds dumb, but can I call on a function from a file? For example, I have a function file full of functions like below (no shell designation):

func { echo "blah blah blah 1" }

func2 { echo "blah blah blah 2" }

func3 { echo "blah blah blah 3" }

(Talking about bash)

Yes, you can use those functions from another file if they have the correct syntax which is not the case.

For bash functions you could have a file say file_number_one.sh:

function func { echo "bla bla bla1"; }

. ./file_number_one.sh

func

ya exactly..
for that you have to source your script as redoubtable suggested..

As an aside, function is a Bashism. The POSIX way to declare a function is

func () { body of function; }