awk command to take a variable

Question

I have a txt file with 3 rows, now I want to multiply a variable value with the 2nd column. Given below is my requirement.

cat sample.txt
    ABC,123,qwe123
    ASD,456,asd123
    VBN,6532,wqe123

I have a variable, colum=100. I want to multiply this variable with 2nd column using awk. The code I tried is:

cat sample.txt | awk -F , '{print $1","$2*$($colum)","$3}'

My expected output is:
        ABC,12300,qwe123
        ASD,45600,asd123
        VBN,653200,wqe123

Please note that I want to perform this awk using the variable only, I dont want to directly multiply column 2 with 100.

Use the builtin `ENVIRON` array to access environment variables: `colum=100 awk -F , '{print $1","$2*ENVIRON["colum"]","$3}' sample.txt` — Phylogenesis, Sep 29 '15 at 08:28

ramana_k · Accepted Answer · 2015-09-29T08:23:45.533

2

You can pass a variable to awk using -v option

cat sample.txt | awk -v colum="100" -F, '{print $1 "," $2 * colum, $3}'

edited Sep 29 '15 at 08:23

answered Sep 29 '15 at 08:18

ramana_k

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The updated command seems to work for me. – ramana_k Sep 29 '15 at 08:29
What if the variable value is not a direct value, the colum value is obtained from some other calculation. How do I pass it to the awk command? – Programmer Sep 29 '15 at 08:32
You can just assign column=$VAR, where VAR is a shell variable. – ramana_k Sep 29 '15 at 08:34
Got it, my problem solved :) thanks – Programmer Sep 29 '15 at 08:36

awk command to take a variable

1 Answers1