# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/{[^}{]*}(*SKIP)(*F)|,//g;t' <<< "{\"A\": \"B\", \"C\":{\"D\":\"E\"}, \"F\": {\"G\"}, \"H\":\"I\"}
{f,o,o} b,a,r {b,a,z}
{{a,a},{b,b},{c,c}}
"
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