Su can execute commands under other user without interaction.

Example:

Normal pipe doesn’t work with kill. Here is what does work.

I have started many java processes and now want to get rid of them:

kill -9 `ps -ef | grep "java" | awk '{print $2}'`

 
Remark: ps -ef | grep "my_token" is a common way to find some process, so if I started tomcat with ./wrapper start I would list it like:

ps -ef | grep "tomcat"

or

ps -ef | grep "wrapper"