Split string into array and print each element on a new line with commandline

Question

I'm having a String which is seperated by commas like a,b,c,d,e,f that I want to split into an array with the comma as seperator. Then I want to print each element on a new line. The problem I'm having is that all cli tools I know so far(sed, awk, grep) only work on lines, but how do I get a string into a format that can be used by these tools. What i'v tried so far is

echo "a,b,c,d,e,f" | awk -F', ' '{print $i"\n"}'

How can I get this output

a
b
c
d
e
f

from this input

a,b,c,d,e,f

?

Answer 1

Sticking with your awk ... just make sure you understand the difference between a field and a record separator :}

echo "a,b,c,d,e,f" | awk 'BEGIN{RS=","}{$1=$1}1'

But the tr solution in the comments is preferable.