Isso deve cobrir isso.
$ cat generic_script.sh
#!/bin/bash
awk_expression="$1"
awk "$awk_expression" file_to_process.txt
$ cat file_to_process.txt
"foo","bar"
$ ./generic_script.sh '{ print $1 }'
"foo","bar"
$ ./generic_script.sh 'BEGIN {FS=","} {gsub(/"/, "", $1); print $1}'
foo
$