How to use awk variables in regular expressions?

Question

I have a file called domain which contains some domains. For example:

google.com
facebook.com
...
yahoo.com

And I have ano

Answer 1

The problem of the answers above is that you cannot use the "metacharacters" (e.g. \< for a word boundary at the beginning of a word) if you use a string instead of a regular expression /.../. If you had a domain xyz.com and two sites ab.xyz.com and cd.prefix_xyz.com, the numbers of the two site entries would be added to xyz.com

Here's a solution using awk's pipe and the sed command: ...

for(dom in domain) {
    while(getline < "./site" > 0) {
        # let sed replaces occurence of the domain at the end of the site
        cmd = "echo '" $1 "' | sed 's/\\<'" dom "'$/NO_VALID_DOM/'"
        cmd | getline x
        close(cmd)
        if (match(x, "NO_VALID_DOM")) { 
          domain[dom]+=$2;
        }
    }
    close("./site") # this misses in original code
}

...