In order to convert a string into an array, create an array from the string, letting the string get split naturally according to the IFS
(Internal Field Separator) variable, which is the space char by default:
arr=($line)
or pass the string to the stdin of the read
command using the herestring (<<<
) operator:
read -a arr <<< "$line"
For the first example, it is crucial not to use quotes around $line
since that is what allows the string to get split into multiple elements.
See also: https://github.com/koalaman/shellcheck/wiki/SC2206