/bin/sh source from stdin (from other program) not file

On systems where /dev/fd is available, bash supports process substitution:

source <(./settings)

Here, <( ) will expand to an automatically assigned path under /dev/fd/... from which the output of ./settings can be read.

You can use eval:

eval "$(./settings)"

eval "`./settings`"

declare `./settings`

Or of course...

export `./settings`

Test it of course...

export `echo -e "asdf=test\nqwerty=dvorak"` ; echo $asdf $qwerty

Handling whitespace:

eval export `./settings`