Sed to extract email addresses from file

sed -e "s/^.*<\(.*\)>.*$/\1/" /file_with_emails | sort | \
uniq | tr "[:upper:]" "[:lower:]"

PS: Filip, he’s terribly smart, I guess the only one to read my blog, pointed out the following one-liner:

sed -nr "s/.*<([A-Z0-9._%-+]+@[A-Z0-9.-]+\.[A-Z]{2,4})>.*/\L\1/pi" \
file_with_emails | sort -u