small uniq trick

[Φρίξος]

O/H Christos Ricudis έγραψε:
> Otan exete ena pelwrio arxeio ths morfhs
> 
> a
> a
> a
> b
> c
> c
> c
> b
> b
> b
> a
> c
> b
> c
> a
> 
> 
> kai 8elete na kanete kati san
> 
> cat lala.koko | sort | uniq
> 
> sas symferei perissotero na kanete
> 
> cat lala.koko | uniq | sort | uniq
> 
> H prwth uniq 8a kopsei ta repetitions sto arxiko arxeio, elafrynontas 
> kata poly to baros ths sort prin to teliko uniq.
> 
OK, I'm stupid. Giati 2 uniq? Meta thn prwth den feygoun OLA ta repetitions?