Linux Script to check if process is running and act on the result

Question

I have a process that fails regularly & sometimes starts duplicate instances..

When I run: ps x |grep -v grep |grep -c \"processname\" I will get: <

Answer 1

In case you're looking for a more modern way to check to see if a service is running (this will not work for just any old process), then systemctl might be what you're looking for.

Here's the basic command:

systemctl show --property=ActiveState your_service_here

Which will yield very simple output (one of the following two lines will appear depending on whether the service is running or not running):

ActiveState=active
ActiveState=inactive

And if you'd like to know all of the properties you can get:

systemctl show --all your_service_here

If you prefer that alphabetized:

systemctl show --all your_service_here | sort

And the full code to act on it:

service=$1
result=`systemctl show --property=ActiveState $service`
if [[ "$result" == 'ActiveState=active' ]]; then
    echo "$service is running" # Do something here
else
    echo "$service is not running" # Do something else here
fi