1.fdisk -l
Disk /dev/sda: 120.0 GB, 120034123776 bytes =>硬盘容量120G
255 heads, 63 sectors/track, 14593 cylinders =>255个磁头，63个扇区，14593个柱面
Units = cylinders of 16065 * 512 = 8225280 bytes =>每个柱面的容量是 8225280
=>存储容量＝磁道（柱面）数×磁头数×每道扇区数×每扇区字节数
14593×255×63×512＝111.788G
柱面容量＝磁头数×每道扇区数×每扇区字节数 255×63×512=8225280 B
实际上硬盘厂家通常是按照1G＝1000计算的
Disk identifier: 0xc3ffc3ff
Device Boot Start End Blocks Id System =>start 表示的一个分区从X cylinder开始
/dev/sda1 * 1 3824 30716248+ 7 HPFS/NTFS
/dev/sda2 3825 10199 51200000 7 HPFS/NTFS
/dev/sda3 10200 12596 19253902+ 5 Extended
/dev/sda4 12597 14593 16040902+ 12 Compaq diagnostics
/dev/sda5 10200 10211 96358+ 83 Linux
/dev/sda6 10212 10454 1951866 82 Linux swap / Solaris
/dev/sda7 10455 11548 8787523+ 83 Linux
/dev/sda8 11549 12596 8418028+ 83 Linux
2.df:通过这个命令可以查看磁盘的使用情况以及文件系统被挂载的位置
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda7 8649544 1986948 6223220 25% /
tmpfs 1033648 0 1033648 0% /lib/init/rw
udev 10240 136 10104 2% /dev
tmpfs 1033648 0 1033648 0% /dev/shm
/dev/sda5 93307 19997 68493 23% /boot
原文：http://www.jb51.net/os/RedHat/1290.html