AWK Programming Notes

Awk is a programming language that can handle and manipulate data. Suppose we have the following data file.

orange 22.5 0
banana 19.5 12
apple 23.0 0
mango 25.0 30
papaya 22.5 25

Print only certain field, first field for instance.

awk '{print $1}' datafile.txt

Print the lines (the whole line, $0) with value at third field is greater than 0.

awk '$3 > 0 {print $0}' datafile.txt

Do some maths (value at second field is multiplied by value at third field) and print.

awk '$3 > 0 {print $1, $2 * $3}' datafile.txt

Print only the lines with value at third field is equal to 0.

awk '$3 == 0 {print $0}' datafile.txt

Print the line that matches given pattern.

awk '/apple/ {print $0}' datafile.txt

Print the line that certain field matches given pattern, exact match and regex match.

awk '$1 == "apple" {print $0}' datafile.txt

awk '$1 ~ /apple/ {print $0}' datafile.txt

Passing variable and matching, and print.

fruit="apple"
awk -v f=$fruit '$0 ~ f {print $0}' datafile.txt

fruit="apple"
awk -v f=$fruit '$1 ~ f {print $0}' datafile.txt