1
echo "1 2 3 4" | awk '{
2
    n = NF
3
    first = 1
4
    for (i = 1; i <= NF; i++) {
5
        coeff = $i
6
        exp = n - i
7
        if (coeff == 0 || exp == 1)
8
            continue
9
        if (!first)
10
            printf "+"
11
        first = 0
12
        if (exp == 0)
13
            printf "%s", coeff
14
        else
15
            printf "%sx^%s", coeff, exp
16
    }
17
    printf "\n"
18
}'