树莓派第四口--Backup

引用：

官翻备份文档

SD CARD IMAGE

It may be sensible for you to keep a copy of the entire SD card image, so you can restore the card if you lose it or it becomes corrupt. You can do this using the same method you‘d use to write an image to a new card, but in reverse.

In Linux or on a Mac, for example:

sudo dd bs=4M if=/dev/sdb of=raspbian.img

This will create an image file on your PC which you can use to write to another SD card, and keep exactly the same contents and settings. To restore or clone to another card, use dd in reverse:

sudo dd bs=4M if=raspbian.img of=/dev/sdb

These files can be very large, and compress well. To compress, you can pipe the output of dd to gzip to get a compressed file that is significantly smaller than the original size:

sudo dd bs=4M if=/dev/sdb | gzip > rasbian.img.gz

To restore, pipe the output of gunzip to dd:

gunzip --stdout rasbian.img.gz | sudo dd bs=4M of=/dev/sdb

======================================================================================