Short way to escape HTML in Bash?

Escaping HTML really just involves replacing three characters: <, >, and &. For extra points, you can also replace " and '. So, it's not a long sed script:

sed 's/&/\&amp;/g; s/</\&lt;/g; s/>/\&gt;/g; s/"/\&quot;/g; s/'"'"'/\&#39;/g'

You can use recode utility:

    echo 'He said: "Not sure that - 2<1"' | recode ascii..html

Output:

    He said: "Not sure that - 2<1"