#command cdx uniq -k3,float
#stdin
 CDX	one	two	three
stuff	junk	1.0
stuff	thing	1.000
junk	junk	-1.0
junk	junk	+1.0
this	that	+1.0e0
#stdout
 CDX	one	two	three
stuff	junk	1.0
junk	junk	-1.0
junk	junk	+1.0