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Full Discussion: creating file of 1MB using shell command?
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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LEARN ABOUT LINUX

irsend

IRSEND(1)							   User Commands							 IRSEND(1)

NAME

       irsend - basic LIRC program to send infra-red commands

SYNOPSIS

       irsend [options] DIRECTIVE REMOTE CODE [CODE...]

DESCRIPTION

       Asks the lircd daemon to send one or more CIR (Consumer Infra-Red) commands. This is intended for remote control of electronic devices such
       as TV boxes, HiFi sets, etc.

       DIRECTIVE can be:
	  SEND_ONCE	    - send CODE [CODE ...] once
	  SEND_START	    - start repeating CODE
	  SEND_STOP	    - stop repeating CODE
	  LIST		    - list configured remote items
	  SET_TRANSMITTERS  - set transmitters NUM [NUM ...]
	  SIMULATE	    - simulate IR event

       REMOTE is the name of a remote, as described in the lircd configuration file.

       CODE is the name of a remote control key of REMOTE, as it appears in the lircd configuration file.

       NUM is the transmitter number of the hardware device.

       For the LIST DIRECTIVE, REMOTE and/or CODE can be empty:

	  LIST	 ""    ""   - list all configured remote names
	  LIST REMOTE  ""   - list all codes of REMOTE
	  LIST REMOTE CODE  - list only CODE of REMOTE

       The SIMULATE command only works if it has been explicitly enabled in lircd.

       -h --help
	      display usage summary

       -v --version
	      display version

       -d --device
	      use given lircd socket [/var/run/lirc/lircd]

       -a --address=host[:port]
	      connect to lircd at this address

       -# --count=n
	      send command n times

EXAMPLES

	  irsend LIST DenonTuner ""
	  irsend SEND_ONCE  DenonTuner PROG-SCAN
	  irsend SEND_ONCE  OnkyoAmpli VOL-UP VOL-UP VOL-UP VOL-UP
	  irsend SEND_START OnkyoAmpli VOL-DOWN ; sleep 3
	  irsend SEND_STOP  OnkyoAmpli VOL-DOWN
	  irsend SET_TRANSMITTERS 1
	  irsend SET_TRANSMITTERS 1 3 4
	  irsend SIMULATE "0000000000000476 00 OK TECHNISAT_ST3004S"

FILES

       /etc/lirc/lircd.conf
	      Default lircd configuration file.  It should contain all the remotes, their infra-red codes and the corresponding timing	and  wave-
	      form details.

DIAGNOSTICS

       If lircd is not running (or /var/run/lirc/lircd lacks write permissions) irsend aborts with the following diagnostics:
       "irsend: could not connect to socket"
       "irsend: Connection refused" (or "Permission denied").

SEE ALSO

       The documentation for lirc is maintained as html pages. They are located under html/ in the documentation directory.

       lircd(8), mode2(1), smode2(1), xmode2(1), irrecord(1), irw(1), http://www.lirc.org.

irsend 0.9.0-pre1						   October 2010 							 IRSEND(1)
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