Go to the Informatica Server directory, and enter the following command:
./pmcmd stopserver <repository username> <repository password> <port #>.
./pmcmd stopserver Administrator Administrator 4001
You can check whether the Informatica Server is running by entering the command
ps -elf |grep pmserver.
If it lists pmserver process, the server is running. If it lists grep pmserver, that is the process of the ps command.