Concepts Glossary 146 Getting Started Guide setenv VARIABLE_NAME variable_value fdisk The fdisk program is a system utility that manages the partitions on your hard disk. After installing Linux, you shouldn’t need to use fdisk again in normal cir- cumstances. You must be logged in as root to use fdisk. If you’re running DOS or Windows, a hard disk utility that is also called FDISK can be used to manage your hard disk. To avoid potential conflicts, remember this rule: if you want to create or modify a partition for use by a certain operating system, use the hard disk utility from that operating system to do it. The fdisk utilities perform many of the same functions of the PartitionMagic pro- gram, but with a character mode interface that assumes you are highly familiar with your hard disk information. CAUTION: Using FDISK on DOS or fdisk on Linux can delete your entire operating system. Use these utilities with great care. File Permissions See Access Rights. Filesystems A filesystem is the place where files and directories on Linux are stored. It con- sists of a formatted area on a device such as a floppy disk or hard disk partition. Because Linux doesn’t use drive letters to refer to multiple filesystems on your computer, you must mount different filesystems into an empty directory on your Linux system so that they can be accessed. Filesystems that Linux can access can be of many different types. These include: • ext2 (the Linux default format) • FAT (msdos) • VFAT (Windows 98, etc.with long filenames) • NFS (remote, network-accessible filesystems) • NTFS (Windows NT filesystems, read only in Linux, write is considered experimental)