Shell Programming and Scripting

LoL OK then ...

so if we consider

Code:

M[$2]=$7

when the value of $2 takes - for example - the value 5 and then 3

The array looks like this :
when $2=5

the M array is
M[1] = unknown
M[2] = unknown
M[3] = unknown
M[4] = unknown
M[5] = $7
M[6] = unknown
...

and when the
$2=3
the M array is
M[1] = unknown
M[2] = unknown
M[3] = $7
M[4] = unknown
M[5] = $7
M[6] = unknown
...

?

or does it build an array such as :
M[5]=$7
M[3]=$7

So that in a way or another, is has an internal mapping table or whatever, in which it hold the order in which the [n] has been entered, so it start by scanning M[5] before M[3] whereas 3<5 ...

???

So in short :

i takes the values of $2 in the for construct, but awk still manage a mapping with an internal index mapping or whatever, which helps it to keep the order in which the M[$2] value are entered (even if $2 does not have ordered values)

Is that correct ? or should i go to buy another brain ?

After line 1 M["AD0081010180947"] contains the value 1010180950
After line 2 M["AD0081010180947"] contains the value 1010180956
after line 3 M["AD0081010180947"] contains the value 1010181014
after line 4 M["AD0081010180947"] still contains the value 1010181014
after line 5 M["AD0081010180947"] contains the value 1010181014 and M["ED0061010180949"] contains the value 1010180956
etc.

Yes,
it's just a sparse associative (keyed by strings) array.

Unless you're using WHINY_USERS (a GNU awk undocumented extention), the internal order of the keys cannot be controlled:

Simpler if not as resource-sparing: sort all by columns 7 reverse (not unique) pipe sort unique column 2. The sort -u saves the first holder of a key value. If you want a sequential presentation on another column, that is a third sort.

Code:

sort -r +6 -7 your_file | sort -u +1 -2

Ok, i think i start to begin to understand ...

Thank you guys for your help & patience sharing your knowledge !

Thanks to everybody, i can now complete my script.