Invoking a script, which has an awk shebang, with parameters (vars)

Question

I have an awk script that I have defined thus:

#!/usr/bin/env awk
BEGIN { if (!len) len = 1; end = start + len }
{ for (i = start; i < end; i++) { print $1 } }

I have saved it as columns and chmod +x'd it. I want invoke it so that start and end are defined as it traverses over a file. I was thinking this should work:

cat some_file | columns -v start=2

But it doesn't. Help!

Answer 1

Try using:

#!/usr/bin/awk -f

as an interpreter

Answer 2

env is the easiest way to handle this problem:

#!/usr/bin/env -S awk -f

to add more options, and to ensure no interference with your arguments, and awk's arguments:

#!/usr/bin/env -S awk -F: -f ${_} --
BEGIN {
    # delete argv[1], which == ENVIRON[_]
    delete ARGV[1]
} # rest of my awk program

as env has a POSIX standard, this shbang should get you around the difficulties of non-standard shbang implementations across unixen.

EDIT

after having written this I realized that '-S' is a non-POSIX compliant FreeBSD env extension. So shell wrapper is probably the way to go, unfortunate as that is.

Answer 3

Below is the answer for this problem -

#!/bin/awk -f