Debug SMTP server

debug_smtpd

#!/bin/sh
# Start a debug SMTP server using Python's smtpd module

show() {
    echo 1>&2 "$@"
}

port=${1-25}
smtpd_args="-c DebuggingServer localhost:$port"

if [ $(whoami) != "root" ]; then
    smtpd_args="-n $smtpd_args"
    if [ $port -lt 1024 ]; then
        show "Listening on TCP port below 1024 requires root."
        show "Did you mean \`sudo $0\`?"
        exit 1
    fi
fi

show "Running on port $port..."
python -m smtpd $smtpd_args
show "Terminated."