Quick script for extracting emails from unformatted text

Often, we face a need of extracting emails from some un-formatted text like or html tags etc. For this, the following script can come handy for extracting emails into simple text file, which can be uploaded to mailman or other mailing software contact lists:
$ more xtract_emails.sh
#/bin/ksh
sed -e ’s/\,/\n/g’ -e ’s/ /\n/g’ $1 | [...]