Fun Things in Life

A lot of time, I need to validate an email address.  There are a lot of PHP/ASP/etc, etc scripts out there to do email validation either based on formatting or connecting back to the SMTP to perform a check.  However, I don’t seem to find any of the validation scripts based on Bash.  Here’s my version:

#!/bin/bash
# check for valid usage
if [ x$1 = 'x' ]
then
echo "Usage: $0 <email address>"
exit 1
fi

# grabbing fields
user=`echo $1 | cut -f1 -d\@`
host=`echo $1 | cut -f2 -d\@`
mxhost=`host -t mx $host | cut -f7 -d\ `
len=`echo $mxhost | wc -c`
len=`expr $len - 2`
mxhost=`echo $mxhost | cut -b1 -$len`

# compose email commands
echo -ne "helo test.com\r\n" > mailcmd
echo -ne "mail from: test\@test.com\r\n" >> mailcmd
echo -ne "rcpt to: $1\r\n" >> mailcmd
echo -ne "quit\r\n" >> mailcmd

# check for mail results
mailresult=`cat mailcmd | nc $mxhost 25| grep ^550 | wc -c`

if [ $mailresult -eq 0 ]
then
echo $1 "is valid"
exit 0
else
echo $1 "is not valid"
exit 1
fi

# clean up
rm mailcmd