Measure the daily number of E-mail messages in a mailbox

This snippet written in bash with calls to perl from the command line measures the number of E-mail messages sent to a mailbox per calendrical day.

#!/bin/bash
grep -h '^Date:' * |
    perl -pe 's!^Date: !!' |
    perl -pe 's!^\w\w\w, !!' |
    perl -pe 's{\d{2}:\d{2}:\d{2}.*$}{}' |
    perl -pe 's!^\s+!!' |
    perl -pae '$_=sprintf("%.2d-%s-%s\n", @F)' |
    sort | uniq -c | sort -n

I used perl for some places where sed would have been more suitable because I find the sed regexp syntax confusing. :-)

Pretty darn good Email validator

This regular expression was written by a friend of mine according to the email spec RFC2822. It should be near 100% coverage of email addresses assuming no leading or trailing whitespace, and no internal linebreaks (you might try 's' at the end to remedy the line break thing but no guarantees).

/^[-^!#$%&'*+\/=?`{|}~.\w]+@[a-zA-Z0-9]([-a-zA-Z0-9]*[a-zA-Z0-9])*(\.[a-zA-Z0-9]([-a-zA-Z0-9]*[a-zA-Z0-9])*)+$/