由于它的破坏性极大，使用时一定要小心!
两个用途，即格式化硬盘和重新对硬盘分区.
1)格式化硬盘
最好进入单用户模式
#format
系统会显示所有的硬盘并让我们选择要操作硬盘：
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c0t0d0
/pci@1f,4000/scsi@3/sd@0,0
1. c0t1d0
/pci@1f,4000/scsi@3/sd@1,0
2. c0t2d0
/pci@1f,4000/scsi@3/sd@2,0
3. c0t3d0 u03
/pci@1f,4000/scsi@3/sd@3,0
Specify disk (enter its number): 2
selecting c0t2d0
[disk formatted]
Warning: Current Disk has mounted partitions.
FORMAT MENU:
disk - select a disk
type - select (define) a disk type
partition - select (define) a partition table
current - describe the current disk
format - format and analyze the disk
repair - repair a defective sector
label - write label to the disk
analyze - surface analysis
defect - defect list management
backup - search for backup labels
verify - read and display labels
save - save new disk/partition definitions
inquiry - show vendor, product and revision
volname - set 8-character volume name
! - execute , then return
quit
format> partition
PARTITION MENU:
0 - change `0' partition
1 - change `1' partition
2 - change `2' partition
3 - change `3' partition
4 - change `4' partition
5 - change `5' partition
6 - change `6' partition
7 - change `7' partition
select - select a predefined table
modify - modify a predefined partition table
name - name the current table
print - display the current table
label - write partition map and label to the disk
! - execute , then return
quit
partition> modify
partition>label
partition>quit
format>save
使用命令newfs来为每一个分区创建文件系统:
newfs /dev/rdsk/c?t?d?s?
硬盘包含启动分区(根分区)，我们需要手动安装启动模块
#reboot cdrom -s (从光盘启动，并进入单用户模式)
#mount /dev/dsk/c0t1d0s0 /mnt (将系统根分区挂接到mnt目录下)
#cp /ufsboot /mnt
#installboot /lib/fs/ufs/bootblk /dev/rdsk/c0t1d0s0 (安装启动模块)
#umount /mnt (卸下挂接)
#reboot (重启动)

2) 重新分区
format命令也可以对硬盘进行重新分区。重新分区后，受影响分区上的所有文件将被清除
要对该分区表命名，SAVE退出format 命令。分区结束后，我们要用newfs命令为改变的分区创建文件系统