Verified and Tested 10/30/15
At some point in their career, everyone is going to troubleshoot an issue. And everyone has their favorite troubleshooting step to use. For a lot of system admins, the first step to do is make sure that everything is up-to-date. For others it’s only a matter of checking log files before finding your solution. For me and others here at Atlantic.Net, it’s lsof; a command line utility used to list information about files that are opened by various processes.
Mostly used for troubleshooting network connection issues, lsof is a powerful yet too-little-known application. If you’re familiar with general Linux commands, lsof is an easy tool to remember because it “lists open files”.
lsof is a Unix-specific command. In order to use it for identifying system information you will need to be using a Unix-style system, such as CentOS or Ubuntu. lsof comes pre-installed on these systems.