List of useful bits of info -- how to do this, how to troubleshoot that, etc.

useful_knowledge.md

Systems Administration

Killing a Dangling SSH Session.

Background: I had previously SSH'd into a server and CD to directory /opt/foo when I got kicked out by network troubles. A colleague was trying to delete that directory and could not delete it.

• SSH into the server
• Execute who to get the active sessions.
• Try to locate the pts/N session from the list.
• Now execute ps -ef | grep -i sshd and from the list, locate the PID for the SSHD session that has pts/N.
• Kill this process, kill -9 PID.

Use logrotate to rotate logfiles on Linux automatically

http://www.vineetmanohar.com/2010/03/howto-rotate-tomcat-catalina-out/

Networking

What causes the Connection Refused message?

http://serverfault.com/questions/725262/what-causes-the-connection-refused-message

Android

Make Android Studio Faster

http://stackoverflow.com/a/30818099/682912