It's common to want to split up large files and the usual method is to use split(1).
If you have a 10GiB file, you'll need 10GiB of free space.
Then the OS has to read 10GiB and write 10GiB (usually on the same filesystem).
This takes AGES.
.
The command uses a set of loop block devices to create fake chunks, but without making any changes to the file.
This means the file splitting is nearly instantaneous.
The example creates a 1GiB file, then splits it into 16 x 64MiB chunks (/dev/loop0 .. loop15).
.
Note: This isn't a drop-in replacement for using split. The results are block devices.
tar and zip won't do what you expect when given block devices.
.
These commands will work:
hexdump /dev/loop4
.
gzip -9 < /dev/loop6 > part6.gz
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cat /dev/loop10 > /media/usb/part10.bin
Show Sample Output
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