Ubuntu – How to use /dev/(u)random

bashkernel

How can I use /dev/(u)random on Ubuntu or any *nix sistems?

I tried this but it says permission denied.
Note : I also tried as root.

/dev/(u)random
sudo /dev/(u)random
sudo -s; /dev/(u)random

Best Answer

It's a file like device, so you can do things like cat it or copy from it. For instance:

dd if=/dev/urandom of=~/urandom_test count=4 bs=1024

Creates a file containing 4K of random bytes. 

cat /dev/urandom > ~/urandom_test2

Will continue to write random bytes to that file until you hit Ctrl-C. Don't do this on a low performing system...

head -30 /dev/urandom > ~/urandom_test3

Will write 30 lines of random bytes

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