Each line that contains CARS is skipped. It'll display x once it comes across a line without CARS, yes. In the end it prints all the lines without CARS, but lagging behind a line (thus the need for the END statement to catch up).
equivalent and quicker: awk '!/CARS/'
That's not correct.
Have the following test file:
You'll see that it skips NULL lines (e.g. line 6 being empty and line 7 being zero).
Also, it does a delayed print: prints the value from the previous line.
When it meets CARS it "NULLs" the saved line (x="") and skips the current line (next).
In the END section the last line is printed (because it was only stored yet).
Hello Friends,
I am new to the scripting & have to analyze bunch of regular production scripts. It has .ksh which calls on the .awk script having many functions
I need to understand and debug the scripts ASAP
Can anybody please let me know as how can I debug, I want to see the flow of code... (3 Replies)
Hi Guys,
I was recently come across some code to hopefully learn a little bit about putting Shell commands into PHP application to run on a Linux server. However, I don't understand the command AT ALL... and was wondering if anyone can interpret it:
cat userIDs.dat | awk '{s=s+1; if... (1 Reply)
Hi
I have an awk script running in ksh in which a section of code is picking out the datetime as follows:
dia=`echo $starttime | nawk '{ printf "%02d\n", substr($1,9,2)}'`
mes=`echo $starttime | nawk '{ printf "%02d\n", substr($1,6,2)}'`
ano=`echo $starttime | nawk '{ printf "%02d\n",... (3 Replies)
i am analyzing a query written by another developer ,need to understand part of script
am looking at a code ..and it converts comma files to pipe delimited and also takes away quotes from any columns,
source field format: 2510,"Debbie",NewYork
changes to
target: 2510|Debbie|NewYork
... (1 Reply)
Hey all,
So I have an AWK command here
awk '{if(FNR==NR) {arr++;next} if($0 in arr) { arr--; if (arr == 0) delete arr;next}{print $0 >"list2output.csv"}} END {for(i in arr){print i >"list1output.csv"}}' list1 list2
(refer to image for a more readable format)
This code was submitted... (1 Reply)
Hi,
Could somebody help me in understanding the following awk expression:
awk -v n="POINT" '/%/{print $0 "\n" n ;next}1' < file name
Thanks,
Arun (6 Replies)
Hi,
I found this in a script and I would like to know how this works
Code is here:
# var1=PART1_PART2
# var2=${var1##*_}
# echo $var2
PART2
I'm wondering how ##* makes the Shell to understand to pick up the last value from the given. (2 Replies)
Hi Experts,
I was looking at the below link, for finding words next to it, And unable to understand this syntax:
Can any one please explain , what is meaning of this code:
if ( F )
s = s ? s OFS $i : $i
from:... (4 Replies)
Hello
I am working on a Change request and Stuck at a point. The below awk command is used in the function.
float_test ( ) {
echo | awk 'END { exit ( !( '"$1"')); }'
}
I understand that awk 'END' is used to add one line at the end and exit is used to end the script with an error... (4 Replies)
Heyas
Recently i wanted to help someone with an awk script, but the end-script didnt work as expected.
He wanted, if HOME was empty, to get the HOME of the current USER from /etc/passwd.
At first i tried hardcoded with root:
awk -F: '/^root/ {print $6}' /etc/passwd
As that worked, i've... (4 Replies)
Discussion started by: sea
4 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)