Sending mail from a Bash shell script

Question

I am writing a Bash shell script for Mac that sends an email notification by opening an automator application that sends email out with the default mail account in Mail.app. The

Answer 1

I whipped this up for the challenge. If you remove the call to 'dig' to obtain the mail relay, it is a 100% native Bash script.

#!/bin/bash
MAIL_FROM="sfinktah@bash.spamtrak.org"
RCPT_TO="sfinktah@bash.spamtrak.org"
MESSAGE=message.txt
SMTP_PORT=25
SMTP_DOMAIN=${RCPT_TO##*@}

index=1
while read PRIORITY RELAY
do
    RELAY[$index]=$RELAY
    ((index++))
done < <( dig +short MX $SMTP_DOMAIN )

RELAY_COUNT=${#RELAY[@]}
SMTP_COMMANDS=( "HELO $HOSTNAME" "MAIL FROM: <$MAIL_FROM>" "RCPT TO: <$RCPT_TO>" "DATA" "." "QUIT" )
SMTP_REPLY=([25]=OK [50]=FAIL [51]=FAIL [52]=FAIL [53]=FAIL [54]=FAIL [55]=FAIL [45]=WAIT [35]=DATA [22]=SENT)

for (( i = 1 ; i < RELAY_COUNT ; i++ ))
do
    SMTP_HOST="${RELAY[$i]}"
    echo "Trying relay [$i]: $SMTP_HOST..."
    exec 5<>/dev/tcp/$SMTP_HOST/$SMTP_PORT
    read HELO <&5
    echo GOT: $HELO
    for COMMAND_ORDER in 0 1 2 3 4 5 6 7
    do
            OUT=${SMTP_COMMANDS[COMMAND_ORDER]}
            echo SENDING: $OUT
            echo -e "$OUT\r" >&5

            read -r REPLY <&5
            echo REPLY: $REPLY
            # CODE=($REPLY)
            CODE=${REPLY:0:2}
            ACTION=${SMTP_REPLY[CODE]}
            case $ACTION in
                    WAIT )          echo Temporarily Fail
                                                    break
                                                    ;;
                    FAIL )          echo Failed
                                                    break
                                                    ;;
                    OK )                            ;;
                    SENT )          exit 0
                                                    ;;
                    DATA )          echo Sending Message: $MESSAGE
                                                    cat $MESSAGE >&5
                                                    echo -e "\r" >&5
                                                    ;;
                    * )         echo Unknown SMTP code $CODE
                                                    exit 2
            esac
    done
done