quick script to extract email ids from a detailed mail header

Since my creative juices are flowing so much today, I thought of posting the simple, yet effective awk script to extract sender’s email ids from a detailed mail message (even though if the mail id be ecrypted).

A word of caution is that the file being processed should have a line with “EOF” value (without strings) ONLY at the end of file, otherwise the awk script will hang.

BEGIN { print FILENAME | "wc -l |cut -f1 -d' '" ; }
/^X-Sender:/ || /^From / { #print NR, $0;
           #
           # get the real userid from where the email came
           #
           m=split($0,b,"@");
           from=b[1];
           #print from;
           x=split(from,c," ");
           realfrom=c[x];
           gsub("<","",realfrom);
           #print realfrom;
           #
           # get the domain name of the smtp server now
           #
           while ($0 !~ /HELO/ && $0 != "EOF") getline;
           if ($0 == "EOF") exit;
           domain=$5; gsub(")","",domain); n=split(domain,a,".")
           #print n, domain;
           realdomain=a[n-1]"."a[n];
           if (n>1) print realfrom"@"realdomain;
           next;
         }