The TF card has 16G, and the img file directly backed up is as big as 16G, but the useful data actually installed in the TF card is only a few gigabytes, and then you need a 32g card to write, so the img file produced by this is too wasteful Space is available, so use this method to compress the disk and make a small img image.
Reference tutorial
https://blog.csdn.net/zhaodeming000/article/details/103198175
https://blog.csdn.net/u013451404/article/details/80552765
View partition information
fdisk -l
Configure partition
sudo e2fsck -f /dev/sda2
sudo resize2fs /dev/sda2 10G
Rebuild the partition:
fdisk /dev/sda
Delete partition:
d
To create a new partition, enter:
n
p
2
【fdisk的起始点】
+10G
Exporting
10504 is calculated using the end sector of sdb2
(the last occupied sector number end 512)/(1024 1024) = 10504
sudo dd if=/dev/sdb of=debian-on-rpi.img bs=1M count=10504
If you want to export to another disk, you need to mount
mkdir /ssc
mount /dev/sdc /ssc
sudo dd if=/dev/sdb of=/ssc/debian-on-rpi.img bs=1M count=10504