Reading Words separated by comma in line

Shell Programming and Scripting
1

Hi All,

I am facing issue, to read words in line, line as follow and i want to read word at each comma

1,you,are,two

So i want read like
1
you
are
two

Thanks

2

If data is in a file:

tr ',' '\n' < file
1
you
are
two

If data is in a variable:

a='1,you,are,two'
echo "${a//,/$'\n'}"
1
you
are
two