Shell Programming and Scripting

    1   2  3
    2   5  7
    4  6   9
    1  5   4
    8  5   7
    1  1 10
   15 3 12
     3 7  9
    9 8 10
    4 5  2
  9 1 10
  4 7 9
  7 12 6
  9 13 8

1    2
2    1
3    1
4    0
5    4
6    1
7    2
8    1
9    0
10    0
11    0
12    1
13    1

nawk '{a[$2]++} END {for (i=1; i<=13;i++) print i, a[i]}' file

1 2
2 1
3 1
4
5 4
6 1
7 2
8 1
9
10
11
12 1
13 1

$ awk '{a[$2]++} END {for (i=1; i<=13;i++) print i, a[i]*1}' file
1 2
2 1
3 1
4 0
5 4
6 1
7 2
8 1
9 0
10 0
11 0
12 1
13 1

$ X= 
$ echo $((X*1))
0

$ echo $((X*1))
ksh: X*1: bad number
$ dtksh -c 'echo $((X*1))'
dtksh -c 'echo $((X*1))'
0
$ bash -c 'echo $((X*1))' 
bash -c 'echo $((X*1))'
0
$