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

Test network speed without wasting disk

Terminal - Test network speed without wasting disk
dd if=/dev/zero bs=4096 count=1048576 | ssh user@host.tld 'cat > /dev/null'
2010-06-08 18:49:51
User: atoponce
Functions: dd ssh
5
Test network speed without wasting disk

The above command will send 4GB of data from one host to the next over the network, without consuming any unnecessary disk on either the client nor the host. This is a quick and dirty way to benchmark network speed without wasting any time or disk space.

Of course, change the byte size and count as necessary.

This command also doesn't rely on any extra 3rd party utilities, as dd, ssh, cat, /dev/zero and /dev/null are installed on all major Unix-like operating systems.

Alternatives

There is 1 alternative - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

This will compress really well with ssh (/dev/zero is the same byte over and over). For a better test replace /dev/zero with /dev/urandom,

Comment by sdadh01 219 weeks ago

The SSH connection is adding overhead with encryption, thus the reason to use /dev/zero to level the playing field, otherwise, your bandwidth will be considerably less.

Comment by atoponce 219 weeks ago

Or you could use netcat and use /dev/urandom. This way you don't have the overhead of compression and use a more realistic approach to test your network.

dd if=/dev/urandom bs=4096 count=1048576 | nc host.tld 1234

and on host.tld you should start netcat with the 'listen' parameter

nc -l -p 1234 | dd of=/dev/null

Actually, if you really wanna test your network you should go the iperf or netperf way (and use UDP or TCP, depending on how you wanna test it).

Comment by paragao 218 weeks and 5 days ago

Right. This isn't meant to be an accurate network bandwidth benchmarking tool. This is useful for nothing more than a rough estimate, and it doesn't rely on any external 3rd party tool, and it's cross platform, which was the goal.

Comment by atoponce 218 weeks and 5 days ago

this command is helpful for a 'rough estimation' but i would add the ssh '-c arcfour' option.

Comment by cp 215 weeks and 2 days ago

Your point of view

You must be signed in to comment.

Related sites and podcasts