Terminal command equivalent of PHP implode when combining lines

Question

I have a couple of lines and want to group the line into 5 and then implode it for MySQL IN () query.

I have made it out until this

awk          


        

Answer 1

#!/usr/bin/awk -f
{
  a[NR] = $0
}
END {
  for (b in a) {
    printf a[b] (b % 5 && b != NR ? "," : RS)
  }
}

Or one liner:

awk '{a[NR]=$0} END {for (b in a) printf a[b] (b%5 && b!=NR ? "," : RS)}'