How to enlarge existing file to specific size

Question

I have hdd.img file, which I user as HDD for my virtual machine, but it's size is too small, how can I enlarge it?

There is one method, something like:

dd if=/dev/zero ds=10GB count=8 >> hdd.img

but it takes a lot of time :(

The command you wrote will completely overwrite the original content. Is that what you want?

Eddy_Em · Accepted Answer · 2013-01-11 11:44:59Z

up vote 6 down vote accepted

Something like that:

dd if=/dev/zero bs=1 seek=new_filesize count=0 of=your_file

For example this:

dd if=/dev/zero bs=1G seek=1000 count=0 of=test

will enlarge file test to 1000G

answered Jan 11 at 11:44

Eddy_Em
3387

	Try it on a test file. It works! All space after old file's content will be filled with "virtual" zeros (sparse file). – Eddy_Em Jan 11 at 11:51
	Oh yes, thank you – atomAltera Jan 11 at 11:52

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