Linux/Unix command to determine if process is running?

Question

I need a platform independent (Linux/Unix|OSX) shell/bash command that will determine if a specific process is running. e.g. mysqld, httpd... What

Answer 1

On most Linux distributions, you can use pidof(8).

It will print the process ids of all running instances of specified processes, or nothing if there are no instances running.

For instance, on my system (I have four instances of bashand one instance of remmina running):

$ pidof bash remmina
6148 6147 6144 5603 21598

On other Unices, pgrep or a combination of ps and grep will achieve the same thing, as others have rightfully pointed out.