Creating a file with specific size

Sometimes we need to add a file with specific file size for testing the download speed etc..
For this you can create a file with specific size by following command:

Lets create a test file with specified size 100Kb.
[root@server ~] # dd if=/dev/zero of=Testfile bs=1024 count=100

Where,
dd – dd is a common UNIX program whose primary purpose is convert and copy a file.
if – Input File. Read from FILE instead of stdin
of – Output File. write to FILE instead of stdout.(The name of the file to be created)
bs – Block Size, mostly in bytes.(Default value is 512bytes)
count – the size of the file to be created  in KB
Now lets see if the file size is as specified

[root@server ~]# ls -l Testfile
-rw-r–r–  1 root  root   102400 Mar  18 06:31 Testfile

You could see the file of specific size will be created for you.