How do I check how many File Descriptors are currently in use ?

Oracle 6300

8.4p3C

We keep getting triggered Minor Alarm that FD count =824 crossed the minimum threshold, total =1024.

I can find the limits from shell using "Ulimit -n" but not the current usage for which i am relying on the Acmelog which only provides information when a syslog entry is generated upon crossing a certain threshold.

I am asking because i cannot reboot the SBC (there was a TLS-Profile and ACP profile mismatch suspected to be causing the issue but fixed now) immediately to clear the FDs but would like to actively monitor the utilization.