Date created: Friday, March 12, 2021 8:36:01 AM. Last modified: Tuesday, August 20, 2024 8:33:01 PM
'dd' Notes
dd commands:
Dump CD to ISO
$ dd if=/dev/cdrom of=/tmp/cdimg1.iso
Generate 10GBs
$ dd if=/dev/zero of=/tmp/image bs=1M count=10000
To view dd progress with more recent dd:
$ time sudo dd status=progress if=ubuntu-18.04.3-4.9-minimal-odroid-n2-20190806.img of=/dev/mmcblk0
To view dd progress when using older dd:
$ dd if=ubuntu-22.04-4.9-minimal-odroid-n2-20220622.img | pv | sudo dd of=/dev/mmcblk0 7944192+0 records in5MiB/s] [ <=> ] 7944192+0 records out 4067426304 bytes (4,1 GB, 3,8 GiB) copied, 555,282 s, 7,3 MB/s 3,79GiB 0:09:15 [6,99MiB/s] [ <=> ] 7944192+0 records in 7944192+0 records out 4067426304 bytes (4,1 GB, 3,8 GiB) copied, 581,472 s, 7,0 MB/s
To view dd progress in a separate terminal when using older dd:
$ sudo dd status=progress if=ubuntu-18.04.3-4.9-minimal-odroid-n2-20190806.img of=/dev/mmcblk0
$ pgrep -l '^dd$'
4858 dd
$ kill -USR1 4858
The progress will be dumped in terminal window where dd is running. Use watch to have continuous output:
$ watch -n 60 'sudo kill -USR1 4858'
To compress a drive copy:
dd if=/dev/hdb | gzip -c > /image.img
To restore a compressed drive copy:
gunzip -c /image.img.gz | dd of=/dev/hdb
Zero out free space on a drive before copying into gzip for better compression:
mkdir /mnt/hdb
mount /dev/hdb /mnt/hdb
dd if=/dev/zero of=/mnt/hdb/zero
rm /mnt/hdb/zero
umount /mnt/hdb
dd if=/dev/hdb | gzip -c > /image.img
Faster copy:
bs=100M conv=notrunc
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