Shell Programming and Scripting

i'm having a hard time understanding the !second{print $0;second=$2;}$2<second{print $0;exit;}' line
.

I want to understand it to tailor it to find 3rd largest maxes with difference greater than 5 (as used in second largest logic), 4th largsest maxes with that same difference, 5th largest, etc. etc.

Thanks for the help so far. I am in unfamiliar territories with awk here.

hi, see this example:

Code:

100
99
98
97
---
80
79
78
77

say max=100

if you want the 2nd largest number is 80

Code:

2nd=80

, then the next smaller should be the 3rd largest (79)

Code:

3rd=79

and you don't have to compare 3rd and max, to check if the difference is > 5.

or you want to ensure that difference between 2nd and 3rd > 5?

---------- Post updated at 17:16 ---------- Previous update was at 17:05 ----------

regarding this line:

Code:

 !second{print $0;second=$2;}$2<second{print $0;exit;}'

if a variable is not assigned any value, it returns false in a boolean check. so "!second" means "if variable <second> has not been set, then do {block}"

yes, i want to ensure between 2nd and 3rd is > 5, and 3rd and 4th is > 5, 4th and 5th > 5, etc. etc.

thanks

Ok.
don't say etc. etc. how many "largest" numbers do you want?
2nd -- ?th
or all as long as possible?

up to 8 largest, with the differences still there (i.e. difference greater than 5 between the previous largest).

thanks for helping me out, I've never gone this far in awk before. But I am learning.

here I made an example, hope that it helps:

Code:

a sorted file (descending) named t

kent$  cat t
foo 100
foo 99
foo 98
foo 97
foo 96
foo 95
foo 94
foo 93
foo 92
....
foo 5
foo 4
foo 3
foo 2
foo 1

awk one liner gives you 8 largest number with 5 as difference with previous :


kent$  awk 'NR==1{max=$2;next;}max-$2>5{print $0;max=$2;c++;}c==8{exit}' t
foo 94
foo 88
foo 82
foo 76
foo 70
foo 64
foo 58
foo 52

thanks this is perfect! thanks for stickin it out with me!