Calling Awk in a shell script

Question

I have this command which executes correctly if run directly on the terminal.

awk '/word/ {print NR}' file.txt | head -n 1

The purpose is to find the line number of the line on which the word 'word' first appears in file.txt.

But when I put it in a script file, it doens't seem to work.

#! /bin/sh

if [ $# -ne 2 ]
then
        echo "Usage: $0 <word> <filename>"
        exit 1
fi

awk '/$1/ {print NR}' $2 | head -n 1

So what did I do wrong?

Thanks,

Answer 1

Replace the single quotes with double quotes so that the $1 is evaluated by the shell:

awk "/$1/ {print NR}" $2 | head -n 1