/bin— This directory contains most of the useful command-line programs and shells you learned about earlier in this chapter. These include echo, bash, zsh, su, and netstat, among others.
/dev— This directory has a special purpose in the Linux file system—it contains files that represent special links to system hardware. For example, in /dev is a file named sda. This file points to the first SCSI hard disk drive, if it exists, in the system. If you have two SCSI hard disk drives, the sdb file would reference the second drive. The hda file points to the first IDE hard disk drive in the system. The fd0 file is a link to the floppy drive A.
/etc— This directory contains configuration files for the various applications and utilities on the system. For example, the fstab file, mentioned earlier in this chapter, is located in this directory. Your hosts file is also located in this directory. If you needed to configure your web server, you would use the httpd.conf file located in the httpd subdirectory of /etc. Because the files in this directory are used to configure the local system, the files in the /etc directory on one Linux system will be different from those on other Linux systems.
/home— This directory contains home directories for every user in the system except for root.
/mnt— This directory is used as a mount point for remote NFS file systems. It is also used to mount a Samba share on a remote server. On some distributions, such as Red Hat, it is used to mount removable media such as floppy disks and CDs.
/media— This directory is unique to SUSE Linux. It is used as a mount point for removable media.
/root— This directory is the root user’s home directory. By default, only root can see this directory.
/tmp— This directory is used for storage of temporary files created by applications.
/usr— This directory is used to store binary program files. For example, gcalc, an X Window System calculator program, is stored in the /usr/bin directory.
/var— This directory has a variety of uses. Manual pages are stored here, as are log files. Data files for services such as named and dhcpd are stored here. You will also see that NNLS stores many of its data files here, as well.