Linux is a very powerful operating system and, consequently, is sometimes complex to understand and configure properly.
Fortunately, all Linux installations give the system administrator access to a number of local document sources like manual pages, info pages and readme files for individual applications.
In addition to those resources, a lot of very relevant information can also be found online. For example,
- The Linux Documentation Project
- The CentOS forum and Redhat documentation
- Freenode, which is an IRC network.
Finally, sometimes a system administrator needs to notify users of changes and disruptions of service.