How to check number of semaphores used by Apache

Introduction

While troubleshooting Apache related start or restart issues it is best to check semaphores used.

Procedure

The following will provide the number of semaphores being used by user nobody.

ipcs -s | tail -n +4 | head -n -1 | tr -s ' ' | cut -d' ' -f3 | sort | uniq -c | sort -nr

and to clear the semaphores the following can be run

for i in `ipcs -s | grep nobody | awk '{print $2}'`; do ipcrm sem $i; done