changing the format of the list

Shell Programming and Scripting
1

I have a file such that

List : a, b, c, d

I want to list this as

List
a
b
c
d

however the trick is the number of arguments in the list is varies. There might be 0-7 variables .

Can you help me?

2 
echo 'List : a, b, c, d'|tr ':,' '\n\n'
3

And what if i have the list such as

a,b,c,d

I couldn't edit it.

4 
$ echo 'a,b,c,d' | tr ':,' '\n\n'
a
b
c
d

Anything wrong with that?

5

It workds thanks..
I tried it before but I didnt realise it worked because of screen settings..

Thanks again..

6 
$ echo " a, b, c, d" | tr ',' '\n'
 a
 b
 c
 d