Linux：

U盘删除分区：

#fdisk /dev/sdb    /*进入fdisk命令操作空间*/
#Command (m for help): m     /*命令查看*/
Command action
a   toggle a bootable flag                   #设置引导扇区
b   edit bsd disklabel                       #编辑卷标（linux下使用的卷标bsd通用）
c   toggle the dos compatibility flag
d   delete a partition                       #删除分区 
l   list known partition types               #列出已知的分区类型 
m   print this menu       
n   add a new partition                      #添加一个新的分区 
o   create a new empty DOS partition table   #生成一个新的空DOS分区列表 
p   print the partition table                #打印分区列表 
q   quit without saving changes              #不保存退出
s   create a new empty Sun disklabel
t   change a partition's system id           #改变一个分区列表的ID 
u   change display/entry units
v   verify the partition table
w   write table to disk and exit             #写入列表到磁盘并退出
x   extra functionality (experts only)#Command (m for help): p
Disk /dev/sdb: 2055 MB, 2055208960 bytes
64 heads, 62 sectors/track, 1011 cylinders
Units = cylinders of 3968 * 512 = 2031616 bytes
Disk identifier: 0x00000000Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         133      263871+   6  FAT16
/dev/sdb2   *         134         200      132928   83  Linux   /*boot 分区*/＃Command (m for help): d
＃Partition number (1-4): 1
＃Command (m for help): pDisk /dev/sdb: 2055 MB, 2055208960 bytes
64 heads, 62 sectors/track, 1011 cylinders
Units = cylinders of 3968 * 512 = 2031616 bytes
Disk identifier: 0x00000000Device Boot      Start         End      Blocks   Id  System
/dev/sdb2   *         134         200      132928   83  Linu＃Command (m for help): d
Selected partition 2＃Command (m for help): p                                      /*查看此时已无分区*/Disk /dev/sdb: 2055 MB, 2055208960 bytes
64 heads, 62 sectors/track, 1011 cylinders
Units = cylinders of 3968 * 512 = 2031616 bytes
Disk identifier: 0x00000000Device Boot      Start         End      Blocks   Id  System＃Command (m for help): w                                      /*最后写入分区表*/
The partition table has been altered!Calling ioctl() to re-read partition table.WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

U盘不分区直接格式化：

/* 在整个/dev/sdb设备上建立文件系统 */＃sudo mkfs -t vfat -I /dev/sdb1         /*在整个/dev/sdb设备上建立文件系统*/

U盘分区并格式化：

/*给磁盘增加一分区并格式化*/＃Command (m for help): n
Command action
e   extended
p   primary partition (1-4)
：p                                                                 /*增加主分区*/
＃Partition number (1-4): 1
＃First cylinder (1-1011, default 1):                               /*回车默认*/
Using default value 1
＃Last cylinder, +cylinders or +size{K,M,G} (1-1011, default 1011): /*回车默认*/
Using default value 1011＃Command (m for help): p                                           /*此时有sdb1分区*/
Disk /dev/sdb: 2055 MB, 2055208960 bytes
64 heads, 62 sectors/track, 1011 cylinders
Units = cylinders of 3968 * 512 = 2031616 bytes
Disk identifier: 0x00000000Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        1011     2005793   83  Linux＃Command (m for help): w                                           /*最后写入分区表*/
The partition table has been altered!Calling ioctl() to re-read partition table.
Syncing disks.＃sudo mkfs -t vfat /dev/sdb1                                       /*分区完成后格式化*/

格式化完成后， 使用U盘之前需要修复一下，修复命令： fsck -t vfat /dev/sdb