# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\(([1-9][\d\-\s,]*[0-9])\)/<span class="ref">$1<\/span>/g;t' <<< "Headaches, intracranial hypertension, papilledema and exophthalmos may occur with intracranial infiltration.(7-15, 8)
(234---345)"
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