With the following example data, both columns are numeric, but the second has different numbers of digits.

2 9

1 1000

1 50

3 0

I want to sort based on both columns. Specifying them separately with the numeric flag, -n, produces the result I want.

sort -n -k1,1 -k2,2 num.data.txt

gives

1 50

1 1000

2 9

3 0

which is what I want.

However,

sort -n -k1,2 num.data.txt

gives data that appear to be sorted alphabetically:

1 1000

1 50

2 9

3 0

I know that sort -n -k1,2 num.data.txt is the same as sort -n num.data.txt (which gives the same result) when there are only two columns, but the data I'm actually working with has more columns.

Why is there this discrepancy between the two methods?

With the following example data, both columns are numeric, but the second has different numbers of digits.

2 9
1 1000
1 50
3 0

I want to sort based on both columns. Specifying them separately with the numeric flag, -n, produces the result I want.

sort -n -k1,1 -k2,2 num.data.txt

gives

1 50
1 1000
2 9
3 0

which is what I want.

However,

sort -n -k1,2 num.data.txt

gives data that appear to be sorted alphabetically:

1 1000
1 50
2 9
3 0

I know that sort -n -k1,2 num.data.txt is the same as sort -n num.data.txt (which gives the same result) when there are only two columns, but the data I'm actually working with has more columns.

Why is there this discrepancy between the two methods?