How to check a service is running or not in Linux?

This is a small "How to" for checking a service is running in the server or not.
Some times we need to check the status of a service if its running or not to cross verify some thing on server.. Suppose you have edited your httpd.conf file and when restarting the service it just show start service is on. But when you try to get access to the web site the site is down. At that time we can use below command to check if Apache service is running or not..
Method 1: Using service command
#service servicename status
#service httpd status
clipped output of the above command

httpd (pid 7474) is running…
Method 2: Using init.d scripts which are located in /etc/init.d folder
/etc/init.d/cron status
Clipped output of init.d script:
cron start/running, process 1253
Method3: Using status command to check if the service is running or not
status atd
atd start/running, process 1245
To check all the services state at a time use below command
#service –status-all