Shell Programming and Scripting

1  a,b,c    2  a,c      3  b,d      4  e,f

1   a    1   b    1   c    2   a    2   c    3   b    3   d    4   e    4   f

{
  for(i=1; i<=NF; i+=2) {
     split($(i+1), tA, ",")
     for(j=1; j in tA; j++)
       printf("%s%s%s%s", (j>1)?OFS:"",$i, OFS,tA[j])
     printf("%s", (i+2>NF)?ORS:OFS)
  }
}

1 a b  c 
2 a c 
3 b d 
4 e f

1 a 
1 b 
1 c 
2 a 
2 c
3 b 
3 d 
4 e 
4 f

perl -nale 'for(1..$#F){ print "$F[0] $F[$_]" }' jhonnyrip.file

awk '{for(i=2;i<=NF;i++){print $1 OFS $i}}'  Input_file

1 a
1 b
1 c
2 a
2 c
3 b
3 d
4 e
4 f