Bash email function

email.sh

#!/bin/bash 

function email {
  local ecode
  GLOBAL_CONTENT=${1:-"[Missing message content]"}
  GLOBAL_SUBJECT=${2:-"$SCRIPT_NAME Message"}
  GLOBAL_TOADDR=${3:-"info@abc.cz"}
  GLOBAL_FROMADDR=${4:-"noreply@abc.cz"}
  [[ "$GLOBAL_TOADDR" =~ ^$EMAILS_REGEX$ ]] \
    || exception "Invalid TO address $GLOBAL_TOADDR"
  [[ "$GLOBAL_FROMADDR" =~ ^$EMAIL_REGEX$ ]] \
    || exception "Invalid FROM address $GLOBAL_FROMADDR"
  # shellcheck disable=2086
  echo -e "$GLOBAL_CONTENT" | base64 | mail \
    -a "Content-Transfer-Encoding: base64" \
    -a "Content-Disposition: inline" \
    -a "Content-Type: text/plain; charset=UTF-8" \
    -aFrom:"$GLOBAL_FROMADDR" \
    -s "=?utf-8?B?$(base64 --wrap=0 <<< "$GLOBAL_SUBJECT")?=" \
    $GLOBAL_TOADDR
  ecode=$?
  log "to $GLOBAL_TOADDR (mail exit code $ecode)" "EMAIL"
  [[ $ecode != 0 && -n "$3" ]] \
    && email "Failed to send e-mail TO: $GLOBAL_TOADDR" "E-mail $SCRIPT_NAME ERROR"
  [[ $ecode == 0 ]]
}