Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.


If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Processor / memory bandwidthd? in GB/s

Terminal - Processor / memory bandwidthd? in GB/s
dd if=/dev/zero of=/dev/null bs=1M count=32768
2009-02-16 12:22:18
Functions: dd
42
Processor / memory bandwidthd? in GB/s

Read 32GB zero's and throw them away.

How fast is your system?

Alternatives

There are 5 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

Quad Core + 6G ram,

34359738368 bytes (34 GB) copied, 3.09455 s, 11.1 GB/s

What you running?

Comment by Williebee 284 weeks and 1 day ago

BTW Nice command!

Comment by Williebee 284 weeks and 1 day ago

Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz

on the same hardware, a different OS...

@CentOS 5.2 x86_64 ... 37.0GB/s

@openSUSE 11 x86_64 ... 13.4GB/s

The OS, Processor and memory-speed have influence on this value... What is your fastest system???

Comment by jacquesloonen 284 weeks and 1 day ago

Very nice command!

On Ubuntu with macbook 4,1 (Intel(R) Core(TM)2 Duo CPU T8300 @ 2.40GHz) I get up to 10.6GB/s with some crap running... I'll try it later on a LFS with nothing at all.

BTW, you get a different answer each time, so run it several times to get an idea.

Comment by gniourf_gniourf 284 weeks and 1 day ago

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 25.1875 s, 1.4 GB/s

This is an Acer Aspire One Netbook running Ubuntu jaunty alpha6

processor: Intel(R) Atom(TM) CPU N270 @ 1.60GHz

Comment by dudus 280 weeks and 4 days ago

mobile@Bills-iPhone ~ $ time dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 285.487 s, 120 MB/s

real 4m45.681s

user 0m0.340s

sys 4m8.030s

Had to try this on my iPhone :)

Comment by my0pic 270 weeks and 5 days ago

PowerEdge R900, 67 GB/sec

Comment by infinity005 270 weeks and 2 days ago

# time dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 enregistrements lus

32768+0 enregistrements ?crits

34359738368 octets (34 GB) copi?s, 18,536 s, 1,9 GB/s

real 0m18.540s

user 0m0.016s

sys 0m18.405s

model name : AMD Athlon(tm) 5000 Dual-Core Processor

Linux version 2.6.32-3-amd64 (Debian 2.6.32-9)

Comment by crashdump 218 weeks and 1 day ago

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 24.6279 s, 1.4 GB/s

On an 8 year old Dell Dimension 8250 (desktop), with Intel Pentium 4 Processor 2.53GHz, 533MHz system bus, Dual Channel PC1066 RDRAM, and 512MB Rambus RDRAM.

Comment by quintic 204 weeks and 4 days ago
dd if=/dev/zero of=/dev/null bs=1048576 count=32768

32768+0 records in

32768+0 records out

34359738368 bytes transferred in 24.666 secs (1393000014 bytes/sec)

That's 1.3GB/s on a Droid X running Froyo. Niiice! ;]

Comment by HerbCSO 192 weeks and 4 days ago

The following was run on a Rackspace Cloud 256MB Server Instance

dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 6.26173 s, 5.5 GB/s

Comment by Nichlas 161 weeks and 3 days ago

# AMD Phenom II X4 955BE, 4Gb ddr3 1333

# mixed Sabayon-Gentoo, 64bits

dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 4.17995 s, 8.2 GB/s

Comment by ivanalejandro0 146 weeks and 6 days ago

[edvin@vampire ~]$ dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 0.614522 seconds, 55.9 GB/s

[edvin@vampire ~]$ cat /proc/meminfo

MemTotal: 3788648 kB

...

[edvin@vampire ~]$ cat /proc/cpuinfo

...

model name : AMD Athlon(tm) II X2 250 Processor

...

cache size : 1024 KB

Comment by cyberpunk 104 weeks and 4 days ago

Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz

OC'd to 3.1 GHz with RAM running at aprox DDR2-1066

4 year old setup still beating some of the recent CPUs :D

dd if=/dev/zero of=/dev/null bs=1M count=32768

32768+0 records in

32768+0 records out

34359738368 bytes (34 GB) copied, 2.21756 s, 15.5 GB/s

Comment by tox2ik 92 weeks and 4 days ago

Your point of view

You must be signed in to comment.

Related sites and podcasts