使用 dd 备份 sd 卡数据
sudo dd bs=4M if=/dev/mmcblk0 | gzip > PiOS.img.gz
mount 文件
使用 parted 命令查看镜像文件分区信息，如下所示：
root@raspberrypi:/media/data/bak/img # parted ./PiOS.img
GNU Parted 3.2
Using /media/data/bak/img/PiOS.img
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) B
align-check TYPE N check partition N for TYPE(min|opt) alignment
help [COMMAND] print general help, or help on COMMAND
mklabel,mktable LABEL-TYPE create a new disklabel (partition table)
mkpart PART-TYPE [FS-TYPE] START END make a partition
name NUMBER NAME name partition NUMBER as NAME
print [devices|free|list,all|NUMBER] display the partition table, available devices, free space, all found partitions, or a particular partition
quit exit program
rescue START END rescue a lost partition near START and END
resizepart NUMBER END resize partition NUMBER
rm NUMBER delete partition NUMBER
select DEVICE choose the device to edit
disk_set FLAG STATE change the FLAG on selected device
disk_toggle [FLAG] toggle the state of FLAG on selected device
set NUMBER FLAG STATE change the FLAG on partition NUMBER
toggle [NUMBER [FLAG]] toggle the state of FLAG on partition NUMBER
unit UNIT set the default unit to UNIT
version display the version number and copyright information of GNU Parted
(parted) unit
Unit? [compact]? y
(parted) print
Model: (file)
Disk /media/data/bak/img/PiOS.img: 31914983424B
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 4194304B 272629759B 268435456B primary fat32 lba
2 272629760B 31914983423B 31642353664B primary ext4
(parted) q
执行如下命令挂载分区：
mount -o loop,ro,offset=4194304 ./PiOS.img /media/data/bak/img/boot
mount -o loop,offset=272629760 /media/data/bak/img/PiOS.img /media/data/bak/img/rootfs