[SOLVED] How to pass !~ (not) case to awk pattern via a bash shell variable

Issue

I have the following file called file.txt.

a,b,c,d
d,c,b,a

I want to run the following file called test.txt:

#!/bin/bash

data=$(cat file.txt)

gib () {
        echo "$1" | awk -v var="$2" 'BEGIN{FS=OFS=","} {if ($1 var~ a) {print $0}}'
}

ti=$(!)

gib "${data}" "$ti"

My goal is to only print:

d,c,b,a

Generally speaking how can I exclude rather than include the awk pattern. I have tried this with /a/ and $1 var~ /a/ without the if construct. But nothing works.

Solution

You can't put operators, or parts of operators, in variables.

If you want to make it conditional whether it looks for a match or non-match, you can take advantage of the fact that the result of a comparison is either 1 or 0, for true or false. So pass in the result you want to test for.

#!/bin/bash

data=$(cat file.txt)

gib () {
    echo "$1" | awk -v var="$2" 'BEGIN{FS=OFS=","} ($1 ~ /a/) == var'
}

ti=0

gib "${data}" "$ti"

Answered By - Barmar

Answer Checked By - Timothy Miller (WPSolving Admin)