# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/(?:(?<!\S)(?:VON|VAN|DE)|\G(?!\A)\S+)\K\x20/-/gim;t' <<< "HENRIETTA VON DER GRAAF
CAROLINE VAN OOSTEN DE WINKEL
MARC DE VRIES VAN JONG
ANNEKA VANHOVEN BAKKER
JOHN SMITH"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html