Q:

Split rows to multiple line based on comma : one liner solution

I want to split the following format to unique lines
Input:
17:79412041:C:T,CGGATGTCAT
17:79412059:C:G,T
17:79412138:G:A,C
17:79412192:C:G,T,A

Desired output
17:79412041:C:T
17:79412041:C:CGGATGTCAT
17:79412059:C:G
17:79412059:C:T
17:79412138:G:A
17:79412138:G:C
17:79412192:C:G
17:79412192:C:T
17:79412192:C:A

Basically split the input to unique rows or firstID:secondID:thirdID:FourthID. Here multiple row may have firstID:secondID:thirdID may be common and the FourthID is the one it make each raw unique(that was seperated by "," in the input).
Thanks in advance
Shams

A:

awk one-liner
$ awk -F":" '{gsub(/,/,":"); a=$1FS$2FS$3; for(i=4; i<=NF; i++) print a FS $i;}' f1
17:79412041:C:T
17:79412041:C:CGGATGTCAT
17:79412059:C:G
17:79412059:C:T
17:79412138:G:A
17:79412138:G:C
17:79412192:C:G
17:79412192:C:T
17:79412192:C:A

We are first replacing all , with : to keep a common delimiter i.e. : 
We are then traversing from 4th field to end and printing each field by prefixing first three fields.

