Question

I am testing awk and got this thought .So we know that

raja@badfox:~/Desktop/trails$ cat num.txt
1   2   3   4
1   2   3   4
4   1   2   31
raja@badfox:~/Desktop/trails$ awk '{ if ($1 == '4') print $0}' num.txt
4   1   2   31
raja@badfox:~/Desktop/trails$ 

so the command going to check for 4 at 1st column in filename num.txt .

So now i want output as there is a 4 at column 4 also and for example if i have 100 column of information and i want get the output as how many columns i have with the term i am searching .

I mean from the above example i want column 4 and column 1 as the output and i am searching for 4 .

Answer 1

You are looking for the NF variable. It’s the number of fields in the line.

Here’s an example of how to use it:

{
    if (NF == 8) {
        print $3, $8;
    } else if (NF == 9) {
        print $3, $9;
    } 
}

Or inside a loop:

# This will print the line if any field has the value 4
for (i=1; i<=NF; i++) {
    if ($i == 4)
        print $0
}