perl -00pe 's#^\[monitor:///var/log/(?:messages|secure|cron|maillog|spooler|audit/audit\.log)\]\n.*^index\s*=\s*\k.+(?=_(?:np|pr)\s*$)#linux#ms' inputs.conf


_DATA_
[monitor:///var/log/cron]
index=NDNW_np
sourcetype=syslog

[monitor:///var/log/maillog]
index=BSKX_np
sourcetype=syslog

[monitor:///var/log/secure]
index=NDNDK_np
sourcetype=syslog

[monitor:///var/log/spooler]
index=DNWN_np
sourcetype=syslog

[monitor:///var/log/audit/audit.log]
index=XBJB_np
sourcetype=syslog

[monitor:///var/log/messages]
index=JNJSJ_pr
sourcetype=syslog

[monitor:///var/log/cron]
index=NCJG_pr
sourcetype=syslog

[monitor:///var/log/maillog]
index=JE3K_pr
sourcetype=syslog

[monitor:///var/log/secure]
index=NLNDKN_pr
sourcetype=syslog

[monitor:///var/log/spooler]
index=EKJC_pr
sourcetype=syslog

[monitor:///var/log/audit/audit.log]
index=QKNK_pr
sourcetype=syslog