How to configure REGEX in a props.conf source stanza to match all sources except ones including "/splunk/"?

Hello, We would like to match all sources except the ones including `/splunk/` in props.conf. Example: No match for `/opt/splunk/var/log/splunk/metrics.log` and `/opt/splunk/var/log/splunk/splunkd.log` We tried several regex variations, but without luck... Thanks, Rainer