# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\G[^ :]*\K /\\ /gm;t' <<< "NetworkManager/system connections/Wired 1.nmconnection:14 address1=10.1.10.71/24,10.1.10.1"
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