Using shell variables in awk

It is possible to use shell variables within a awk command in a shell script.
As mentioned in the GNU Awk official documentation, one use case is that the shell variable holds the pattern that will be used by awk.
Here is one of the given examples :

printf "Enter search pattern: "
read pattern
awk -v pat="$pattern" '$0 ~ pat { nmatches++ }
END { print nmatches, "found" }' /path/to/data

If the pattern search is a bit more complicated than the one below $0 ~ pat, then this feature does not work anymore.

More details :

AWK : Using Shell Variables in Programs

Learning Awk

A couple of useful AWK Tutorial to guide you through learning and mastering Awk :