Linux dd create multiple iso files

Question

I want to create an iso from an external hard drive. I used this command:

sudo dd if=/dev/sdb of=usb-image.iso

It works, however, the disk is large (700 GB), and i dont have space on my laptop to store that much. I was thinking about creating multiple iso files (each file 5 GB for example), this way, I can manage them by storing some parts on other drives.

Any help? Thanks

It's more of a fit for SuperUser, consider using block size and count (see the manpage for details) — mszymborski, Aug 17 '16 at 18:34
[first google try](http://www.linuxquestions.org/linux/answers/applications_gui_multimedia/splitting_and_merging_files_using_dd) — Emilio Pastor Mira, Aug 17 '16 at 18:37

score 0 · Accepted Answer · answered Aug 17 '16 at 19:20

I'd use the split program to split the output from dd into different files. You can adjust the split size as you see fit (look at the 5000m argument):

dd if=/dev/sdb | split -b 5000m - /tmp/output.gz

This will yield files like /tmp/output.gz.aa, /tmp/output.gz.ab, etc.

Additionally, for further space storage, you can gzip your archive midstream, like this:

dd if=/dev/sdb | gzip -c | split -b 5000m - /tmp/output.gz

Later, when you want to restore, do this:

cat /tmp/output.gz.* | gzip -dc | dd of=/dev/sdb

Linux dd create multiple iso files

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