bash sort from the end of string

Question

I want to sort file by first file, but the last character is the most important.

For example form file:

"AAAACTTTTT"                    1       2

"AAAACAAAAA"    1       2       6       4

To:

"AAAACAAAAA"    1       2       6       4

"AAAACTTTTT"                    1       2

I tried:

sort -k1,1 file

Of course it doesn't work, but I have no idea how I can do this. Could you help me? Mayby some secret flags?

Answer 1

I wanted to sort (group) a list of email addresses by their domain names e.g. all '@xxx.com' then all the '@yyy.com' (solution based on a comment by makgun)

rev emailist | sort | rev > emailistsorted

to just get uniques

rev emailist | sort -u | rev > emailistsorted

Answer 2

If the file isn't too big, you can do it with GNU awk:

{
    count = split($1, arr, "");
    key = ""
    for (i = 1; i <= count; i++) {
        key = arr[i] key;
    }
    lines[key] = $0;
}
END {
    count = asort(lines);
    for (i = 1; i <= count; i++) {
        print lines[i];
    }
}