In a Linux shell how can I process each line of a multiline string?

Question

While in a Linux shell I have a string which has the following contents:

cat
dog
bird

and I want to pass each item as an argument to another fu

Answer 1

Just pass your string to your function:

function my_function
{
    while test $# -gt 0
    do
        echo "do something with $1"
        shift
    done
}
my_string="cat
dog
bird"
my_function $my_string

gives you:

do something with cat
do something with dog
do something with bird

And if you really care about other whitespaces being taken as argument separators, first set your IFS:

IFS="
"
my_string="cat and kittens
dog
bird"
my_function $my_string

to get:

do something with cat and kittens
do something with dog
do something with bird

Do not forget to unset IFS after that.