# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/"?(\w+)='?([\w]+)'?"?|"?(\w+)="([\w\s]+)""?/"$1$3='$2$4'"/g;t' <<< "foo a='b' c=\"d and e\" wombat=true a fizz='buzz' \"hello='goodbye'\""
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