linux对一个新硬盘sdb进分区，要求划分有两个主分区，一个扩展分区，两个逻辑分区，分区大小自行决定

好的，下面是对新硬盘sdb进行分区的步骤：

1. 使用fdisk命令对硬盘进行分区，命令如下：

sudo fdisk /dev/sdb

2. 输入`n`创建新分区，选择`p`创建主分区，输入分区号（1或2），然后输入起始扇区和结束扇区，这里以默认值为例。

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-10485759, default 2048): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-10485759, default 10485759): 

Created a new partition 1 of type 'Linux' and of size 5 GiB.

3. 接着创建第二个主分区，同样按照上述步骤操作。

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2): 2
First sector (10485760-10485759, default 10485760): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (10485760-10485759, default 10485759): 

Created a new partition 2 of type 'Linux' and of size 5 GiB.

4. 创建扩展分区，同样按照上述步骤操作。

Command (m for help): n
Partition type
   p   primary (2 primary, 0 extended, 2 free)
   e   extended (container for logical partitions)
Select (default p): e
Partition number (2-4, default 3): 
First sector (10485760-10485759, default 10485760): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (10485760-10485759, default 10485759): 

Created a new partition 3 of type 'Extended' and of size 9 GiB.

5. 接下来创建两个逻辑分区，同样按照上述步骤操作。

Command (m for help): n
Partition type
   p   primary (2 primary, 1 extended, 1 free)
   l   logical (numbered from 5)
Select (default p): l
Adding logical partition 5
First sector (10485761-10485759, default 10485761): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (10485761-10485759, default 10485759): 

Created a new partition 5 of type 'Linux' and of size 4 GiB.

Command (m for help): n
Partition type
   p   primary (2 primary, 1 extended, 0 free)
   l   logical (numbered from 5)
Select (default p): l
Adding logical partition 6
First sector (12582912-10485759, default 12582912): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (12582912-10485759, default 10485759): 

Created a new partition 6 of type 'Linux' and of size 1 GiB.

6. 最后使用`w`命令保存分区表。

Command (m for help): w
The partition table has been altered.
Syncing disks.

7. 分区完成后，可以使用`lsblk`命令查看分区信息。

$ lsblk /dev/sdb
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb      8:16   0  20G  0 disk 
├─sdb1   8:17   0   5G  0 part 
├─sdb2   8:18   0   5G  0 part 
├─sdb3   8:19   0   9G  0 part 
├─sdb5   8:21   0   4G  0 part 
└─sdb6   8:22   0   1G  0 part