Sort one column only, keeping remaining columns untouched

Question

How to (numerically) sort a specific column in a text file, without affecting other columns (irrespective of whether they are sorted or unsorted)? On other threads I found -s argument, but it does sort other columns.

Observation

$ cat tmp.txt
1 1
2 3
5 4
1 3

$ sort -s -n -k1,1 tmp.txt
1 1
1 3
2 3
5 4

Answer 1

As mentioned in the comments, you can't achieve what you want using sort alone.

You could cut the input file, feed relevant part to sort, and paste those.

$ paste -d' ' <(cut -d' ' -f1 input | sort -n) <(cut -d' ' -f2- input)
1 1
1 3
2 4
5 3

Answer 2

A solution in perl:

perl -lane '
 push @first , $F[0];
 push @second, $F[1];
 END{
    @first = sort { $a <=> $b } @first;
    print "$fist[$_] $second[$_]" for (0..$#first)
 }' your_file

It assumes the first column (the one to be sorted) consists only of numerical data.

Answer 3

I'm on solaris and needed an answer without sort -s and the accepted answer wasn't working for me. Joeyg on unix.com had the answer: sort-one-column-only

cat tmp.txt
1 5
2 3
5 4
1 3

#Sort by 1st column leaving second stable sorted by the 1st.
cat -n tmp.txt | sort -k 2,2 | awk '{print $2,$3}'
1 5
1 3
2 3
5 4

#Sort by 2nd column leaving first stable sorted by the 2nd.
cat -n tmp.txt | sort -k 3,3 | awk '{print $2,$3}'
2 3
1 3
5 4
1 5

Different interpretation via comment is to sort a single column without affecting the rest:

#Sort by 1st column leaving other columns untouched:
cat -n tmp.txt | sort -k 2,2 | awk '{a[NR]=$2;b[$1]=$3} END {for (i=1;i<=NR;i++)print a[i]" "b[i]}'
1 5
1 3
2 4
5 3

Explanation:
cat -n adds rownums to force sort to do "sort -s" without GNU sort.
sort -k 2,2 sorts by the 1st column

NR is a built-in variable that holds the row num.
a[NR]=$2; puts the sorted column in a[1..4]
b[$1]=$3; puts the "unsorted" 2nd column in b[rownum from cat]
Then the for loop just outputs the two arrays.

What I needed which was the newest unique column 3 entries in the file. e.g.

cat tmp2.txt
5|1|3
4|2|1
1|3|2
3|4|1
2|5|2

cat -n tmp2.txt | sort -k 3 -rut '|' | awk '{print $2}'
5|1|3
2|5|2
3|4|1