gawk < /etc/passwd '     BEGIN   {
	uid[void] = "" 										# tell gawk that uid is an array
	}
	{										# no pattern indicates process all records
	dup = 0										# initialize duplicate flag
	split($0, field, ":")										# split into fields delimited by ":"
	if (field[2] == "")										# check for null password field
		{
		if (field[5] == "")									# check for null info field
			{
			print field[1] " has no password."
			}
		else
			{
			print field[1] " ("field[5]") has no password."
			}
		}
	for (name in uid)										# loop through uid array
		{
		if (uid[name] == field[3])									# check for second use of UID
			{
			print field[1] " has the same UID as " name " : UID = " uid[name]
			dup = 1								# set duplicate flag
			}
		}
	if (!dup)										# same as if (dup == 0)
											# assign UID and login name to uid array
		{
		uid[field[1]] = field[3]
		}
	}'