# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\|("[^,]+")\|/$1/gm;t' <<< "(STR,0:30) + |\"Outdoor\"| + |\"Chair Mat\",\"Commercial Floor Mat\",\"Door Mat\"| + [Post Type] + (STR,0:30)"
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