If you can use a simple delimiter, a very simple oneliner is this:
for i in a,b c_s,d ; do
KEY=${i%,*};
VAL=${i#*,};
echo $KEY" XX "$VAL;
done
Hereby i
is filled with character sequences like "a,b"
and "c_s,d"
. each separated by spaces. After the do
we use parameter substitution to extract the part before the comma ,
and the part after it.