Shell Programming and Scripting

user1,location1,location2,locatoin3,seat1,seat2,seat3
user2,location1,seat1
user3
user4,location1,location2,seat1,seat2

user1,location1,seat1
user1,location2,seat2
user1,location3,seat3
user2,location1,seat1
user3
user4,location1,seat1
user4,locatoin2,seat2

awk -F, ' {
                if ( NF > 3 )
                {
                        n = (NF - 1) / 2
                        for ( i = 2; i <= (n + 1); i++ )
                        {
                                print $1, $i, $(i + n)
                        }
                }
                else
                {
                        print $0
                }
} ' OFS="," file

awk -F, '
function prt(start,end,inc,user,FN)
{
  for(i=start;i<end;i++)
    print user,$i,$(i+inc) >> FN
}
{
  for(i=1;i<=NF;i++)if(match($i,"user")){pos=i;break}
  x=((NF-pos)/2)
  prt(pos+1,pos+1+x,x,$pos,"RH")
  y=(pos-1)/2
  prt(1,y+1,y,$pos,"LH")
}' OFS=, infile

LH and RH files will be created