Running Linux, 5th Edition - Matthias Kalle Dalheimer [181]
Like any powerful tool, the root account can be abused. It is important, as the system administrator, to protect the root password, and if you give it out at all, to give it only to those users who you trust (or who can be held responsible for their actions on the system). If you're the only user of your Linux system, this certainly doesn't apply—unless, of course, your system is connected to a network or allows dial-in login access.
The primary benefit of not sharing the root account with other users is not so much that the potential for abuse is diminished, although this is certainly the case. Even more important is that if you're the one person with the ability to use the root account, you have complete knowledge of how the system is configured. If anyone were able to, say, modify important system files (as we'll talk about in this chapter), the system configuration could be changed behind your back, and your assumptions about how things work would be incorrect. Having one system administrator act as the arbiter for the system configuration means that one person always knows what's going on.
Also, allowing other people to have the root password means that it's more likely someone will eventually make a mistake using the root account. Although each person with knowledge of the root password may be trusted, anybody can make mistakes. If you're the only system administrator, you have only yourself to blame for making the inevitable human mistakes as root.
That being said, let's dive into the actual tasks of system administration under Linux. Buckle your seatbelt.
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[*] At least one author attests a strong correspondence between Linux system administration and Robert Pirsig's Zen and the Art of Motorcycle Maintenance. Does Linux have the Buddha nature?
[*] Notice that the Unix kernel does not care about the username actually being root: it considers everybody who has the user ID 0 to be the superuser. By default, the username root is the only username mapped to that user ID, but if you feel like it, you can always create a user named thebigboss and map that to user ID 0 as well. The next chapter will show you how to do that.
Managing Filesystems
You probably created filesystems and swap space when you first installed Linux (most distributions help you do the basics). Here is a chance to fine-tune these resources. Most of the time, you do these things shortly after installing your operating system, before you start loading up your disks with fun stuff. But occasionally you will want to change a running system, for example, to add a new device or perhaps upgrade the swap space when you upgrade your RAM.
To Unix systems, a filesystem is some device (such as a hard drive, floppy, or CD-ROM) that is formatted to store files. Filesystems can be found on hard drives, floppies, CD-ROMs, and other storage media that permit random access. (A tape allows only sequential access, and therefore cannot contain a filesystem per se.)
The exact format and means by which files are stored is not important; the system provides a common interface for all filesystem types it recognizes. Under Linux, filesystem types include the Third Extended filesystem, or ext3fs, which you probably use to store Linux files; the Reiser filesystem, another popular filesystem for storing Linux files; the VFAT filesystem, which allows files on Windows 95/98/ME partitions and floppies to be accessed under Linux (as well as Windows NT/2000/XP partitions if they are FAT-formatted); and several others, including the ISO 9660 filesystem used by CD-ROM.
Each filesystem type has a very different underlying format for storing data. However,