UNIX for Dummies Questions & Answers

Hello.


Could anyone help me with my little annoying problem?
I have to generate a 512 MB file made up with random data using DD. After some internet digging I found out that the command is:

Code:

dd if=/dev/urandom of=/exemple/file bs=512MB

After running this command the shell is not responding anymore, so I have to hit ctrl + z to end the process. Why does it freeze? I need to be able to run ps to see the dd's proces PID because meanwhile the dd is running, I have to check the progress using some strange command:

Code:

  kill -USR1 `pidof dd`

If u did understend what I am talking about, cuz I am a bit confuse, please help me.

That thread is about files made up with zero. I need one with random data, using random/urandom, but still it helps. thanks

---------- Post updated at 07:16 PM ---------- Previous update was at 07:11 PM ----------

Anyway, could u tell me if it is suppose to freeze? When I execute

Code:

dd if=/dev/urandom of=file bs=1MB count=512

the bash freezez and after an certain amout of time it ends. The file is created 512MB, hurray.
But I have to run a signal during the DD process to check the progress. I searched on the internet and I found this signal for checking the progress:

Code:

kill -USR1 `pidof dd`

. But how I am supposed to check the DD pid and after to run this signal if the bash freezes after executing the dd line?

Add an ampersand at the end of your command to start it in the background:

Code:

dd if=/dev/urandom of=file bs=1MB count=512&

then you can use:

Code:

ls -l file

to see the progress of the dd command (by checking the size of the file reported by ls).