Question

I have a file like this:

1 2 3 
4 5 6
7 6 8
9 6 3
4 4 4

What are some one-liners that can output unique elements of the nth column to another file?

EDIT: Here’s a list of solutions people gave. Thanks guys!

cat in.txt | cut -d' ' -f 3 | sort -u
cut -c 1 t.txt | sort -u
awk '{ print $2 }' cols.txt | uniq
perl -anE 'say $F[0] unless $h{$F[0]}++' filename

Answer 1

Corrected: Thank you Mark Rushakoff.

$ cut -c 1 t.txt | sort | uniq

or

$ cut -c 1 t.txt | sort -u


1
4
7
9