CODEWITHSUNDEEP
bashshellawk
user13210771
user13210771

Reputation: 27

How $0 is used in awk, how it works?

read n
awk '
    BEGIN {sum=0;}{if( $0%2==0 ){sum+=$0;
     }
     }
     END { print sum}'

Here i add, sum of even numbers and what i want is, initially i give input as how many(count) and then the numbers i wanted to check as even and add it. eg) 3 6 7 8 output is : 14 here 3 is count and followed by numbers i want to check, the code is executed correctly and output is correct, but i wanted to know how $0 left the count value i.e) 3 and calculates the remaining numbers.

Upvotes: 0

Views: 849

Answers (2)

karakfa
karakfa

Reputation: 67507

you're reading the count but not using it in the script, a rewrite can be

$ awk 'NR==1  {n=$1; next}             // read the first value and skip the rest
      !($1%2) {sum+=$1}                // add up even numbers
       NR>n   {print sum; exit}' file  // done when the # linespass the counter.

in awk, $0 corresponds to the record (here the line), and $i for the fields i=1,2,3... even number is the one with remainder 0 divided by 2. NR is the line number.

Upvotes: 1

user1934428
user1934428

Reputation: 22247

Please update your question to be meaningful: There is no relationship between $0 and the Unix operating system, as choroba already pointed out in his comment. You obviously want to know the meaning of $0 in the awk programming language. From the awk man-page in the section about Fields:

$0 is the whole record, including leading and trailing whitespace.

Upvotes: 1

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