# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/^.*?(IDC\w*)[\s\S]*?(?:$|(,\n.*$))(\n|$)/$1\n/gmi;t' <<< " LTEXT \"Width\",IDC_WIDTH_TEXT,203,74,22,10
EDITTEXT IDC_WIDTH_IN,244,73,57,12,ES_AUTOHSCROLL | WS_GROUP
CONTROL \"Manually scale instances and paper\",IDC_RAD_PSCALE_KEYIN,
\"Button\",BS_AUTORADIOBUTTON | WS_GROUP | WS_TABSTOP,15,89,132,10
CONTROL \"Keep drawing instance scale 1.0\",IDC_RAD_PSCALE_AUTO,
\"Button\",BS_AUTORADIOBUTTON,15,104,123,10
CONTROL \"Keep drawing paper scale 1.0\",IDC_RAD_ISCALE_AUTO,
\"Button\",BS_AUTORADIOBUTTON,15,119,118,10"
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