Create file of 2 GB

Swapna173 · 09-01-2008, 02:31 AM

Hi Guys,

I wanted to create a 2 GB file on the currenct directory. with any values but its size shld be 2 GB.

How can i create a 2 GB file through scripting and check its size shld go till 2 GB.

w3bd3vil · 09-01-2008, 02:55 AM

i am not sure if this is what you wanted

Quote:

dd if=/dev/urandom of=/tmp/2gbfile count=4M

mohans.grd@gmail.com · 09-01-2008, 02:59 AM

Quote:

Originally Posted by Swapna173

Hi Guys,

I wanted to create a 2 GB file on the currenct directory. with any values but its size shld be 2 GB.

How can i create a 2 GB file through scripting and check its size shld go till 2 GB.

Easy way to create 2gb file

Go to that current directoy
#dd if=/dev/zero of=filename bs=1024 count=2GB

mohans.grd@gmail.com · 09-01-2008, 03:00 AM

Easy way to create 2gb file

Go to that current directoy
#dd if=/dev/zero of=filename bs=1024 count=2GB

Swapna173 · 09-01-2008, 03:35 AM

Quote:

Originally Posted by mohans.grd@gmail.com

Easy way to create 2gb file

Go to that current directoy
#dd if=/dev/zero of=filename bs=1024 count=2GB

this command is creating file of size more than 2 GB. How can i restrict to 2 GB exactly.

w3bd3vil · 09-01-2008, 03:40 AM

now, now, read a bit.

Quote:

man dd

or play around with the commands

Quote:

dd if=/dev/zero of=filename bs=1024 count=100
dd if=/dev/zero of=filename bs=1024 count=1000
dd if=/dev/zero of=filename bs=1024 count=10000
dd if=/dev/zero of=filename bs=1024 count=200000

Analyse the output, hopefully you will understand.

mohans.grd@gmail.com · 09-01-2008, 04:27 AM

dd if=/dev/zero of=filename bs=1024 count=2M

Swapna173 · 09-01-2008, 04:28 AM

Quote:

Originally Posted by w3bd3vil

now, now, read a bit.

or play around with the commands

Analyse the output, hopefully you will understand.

Hey thanks.

This one worked.

jschiwal · 09-01-2008, 05:03 AM

Look at the "seek" option of dd. Since you don't care about it being zeroed out or have psuedorandom numbers, creating a file by using an offset will be quicker.

Code:

 dd bs=1024 count=1 seek=$((1024*1024*2-1)) if=/dev/zero of=dummyfile

This will seek to 1024 bytes shy of 2GB and write one 1024 byte block to finish.