UNIX for Dummies Questions & Answers

This does work:

Code:

cat testdata |sort -t / -k3.6n

I was using -k2.6n and this did not work. Why are there considered to be 3 fields? to me the delimiter separates each field and there are only 2 fields. I am trying to study the man page but am still not sure how 3 fields are obtained.

Perhaps this awk example helps to show how fields are divvied up with forward slash as the delimiter...with the 1st field always being the one that is to the left of the first delimiter...

Code:

echo a/b | awk -F/ '{print $1, $2}'
a b

> echo /b | awk -F/ '{print $1, $2}'
 b

> echo /b | awk -F/ '{print $1 ? $1 : "null", $2}'
null b

Hope this helps...

If you are using separators the pattern for a line is:

Code:

<field><separator><field><separator><field><separator><field>...

Therefore, if the first character in your line is a separator that means that field 1 is just empty. Otherwise there would be no way to have completely empty fields at the beginning of the line. Consider:

Code:

some//thing

It can intuitively seen that in this case field 1 contains "some", field 3 contains "thing" and field 2 is empty. Now, what goes for field 2 should also go for field 1, yes? How should a line with an empty field 1, empty field 2 and field 3 = "thing" look like, hmm?

I hope this helps.

bakunin