Question

infile:

1   3
2   3
3   3
4   3
8   3
9   3
12  3
14  3
18  3
19  3
20  3
25  3
26  3
27  3
28  3
30  3
31  3
32  3
36  3
38  3
101 3
109 3

Once I knew a one liner to count the decade occurrences. E.g. 5 thirties…
I hope you do now. A python script would be awesome.

Desired output:

0    6
1    4
2    5
3    4
10    2

Answer 1

An awk one-liner for you –

awk '{x=$1/10; a[int(x)]++} END{for(i in a) print i,a[i] | "sort -n"}' INPUT_FILE

Test:

[jaypal:~/Temp] cat file
1   3
2   3
3   3
4   3
8   3
9   3
12  3
14  3
18  3
19  3
20  3
25  3
26  3
27  3
28  3
30  3
31  3
32  3
36  3
38  3
101 3
109 3

[jaypal:~/Temp] awk '{x=$1/10; a[int(x)]++} END{for(i in a) print i,a[i] | "sort -n"}' file
0 6
1 4
2 5
3 5
10 2