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Top Forums Shell Programming and Scripting creating file of 1MB using shell command? Post 302070346 by matrixmadhan on Tuesday 4th of April 2006 07:47:19 AM
Old 04-04-2006
Quote:
Originally Posted by vino
Try this.

Code:
dd if=/dev/zero of=output.file bs=1024 count=1024

It will be filled with /dev/zero's
this is just a suggestion,
when generating files of huge size,
it is better you attack from the block size thereby reducing the count

for a 1 MB file,
Code:
dd if=/dev/zero of=output.file bs=1024 count=1024

time taken = 0.13 s
Code:
dd if=/dev/zero of=output.file bs=1048576 count=1

time taken = 0.08 s
it is just a difference of (0.13 - 0.08) s

but consider generating some 200 MB files
attacking block size would surely provide a difference.

Last edited by Yogesh Sawant; 02-26-2010 at 02:39 PM.. Reason: added code tags
 

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shell(1F)							   FMLI Commands							 shell(1F)

NAME
shell - run a command using shell SYNOPSIS
shell command [command] ... DESCRIPTION
The shell function concatenate its arguments, separating each by a space, and passes this string to the shell ($SHELL if set, otherwise /usr/bin/sh). EXAMPLES
Example 1: A sample output of shell command. Since the Form and Menu Language does not directly support background processing, the shell function can be used instead. `shell "build prog > /dev/null &"` If you want the user to continue to be able to interact with the application while the background job is running, the output of an exe- cutable run by shell in the background must be redirected: to a file if you want to save the output, or to /dev/null if you don't want to save it (or if there is no output), otherwise your application may appear to be hung until the background job finishes processing. shell can also be used to execute a command that has the same name as an FMLI built-in function. NOTES
The arguments to shell will be concatenate using spaces, which may or may not do what is expected. The variables set in local environments will not be expanded by the shell because "local" means "local to the current process." ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
sh(1), attributes(5) SunOS 5.10 5 Jul 1990 shell(1F)
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