sort and uniq columns individually in a text file

Question

I have a file as below:

D F T E
A R T E
K A O E
E T P J

I would like to sort each column and unique the columns individually as below:

A A O E
D F P J
E R T
K T

I wonder if there is anyone who knows how to use sort or uniq to do so?

Answer 1

You can try something like this:

paste -d'\t' <(cut -f 1 -d' ' file | sort -u) <(cut -f 2 -d' ' file | sort -u) <(cut -f 3 -d' ' file | sort -u) <(cut -f 4 -d' ' file | sort -u) >output

I put tab as delimiter of paste to be more visible the output.

Answer 2

(I like the paste/cut answer of @taliezin. Here's a more prosaic solution in case of many columns). Split the data into one file per column, sort these files, and merge back the files. I'm assuming fixed-width columns of 1 character, to cope with column 2 being shorter than column 3, for example. In this demo data0 is the initial file:

for i in {1..4}
do  awk -v i=$i '{ch = substr($0,i*2-1,1);if(ch!=" ")print ch}' </tmp/data0 |
    sort -u >/tmp/data$i
done
awk -v rows=$(wc -l </tmp/data0) '
BEGIN{
    for(i=1;i<=4;i++)
       file[i] = "/tmp/data" i
    while(rows-->0){
        for(i=1;i<=4;i++){
             d = ""
             getline d <file[i]
             printf("%1s ",d)
        }
        printf "\n"
    }
}' </dev/null