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.

Universal configuration monitoring and system of record for IT.

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:



May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

Top Tags



Using bash inline

Terminal - Using bash inline
<<<"k=1024; m=k*k; g=k*m; g" bc
2009-06-17 10:35:10
User: mpb
Using bash inline

There are two ways to use "here documents" with bash to fill stdin:

The following example shows use with the "bc" command.

a) Using a delimiter at the end of data:

less-than less-than eeooff bc

> k=1024

> m=k*k

> g=k*m

> g

> eeooff


b) using the "inline" verion with three less-than symbols:

less-than less-than less-than "k=1024; m=k*k; g=k*m; g" bc


One nice advantage of using the triple less-than version is that the command can easily be recalled

from command line history and re-executed.

PS: in this "description", I had to use the name "less-than" to represent the less-than symbol because the commandlinefu input text box seems to eat up the real less-than symbols. Odd.


There are 3 alternatives - vote for the best!

Terminal - Alternatives
command <<< word
2012-02-29 03:14:54
User: adeverteuil
Functions: command
Tags: bash stdin

Don't do this:

echo word | command

Using a bash "here strings" and "here documents" look leeter than piping echo into the command. Also prevents subshell execution. Word is also expanded as usual.

Know a better way?

If you can do better, submit your command here.

What others think

Why not simply use echo?

echo "k=1024; m=k*k; g=k*m; g" | bc

I think it's easier to understand, and it's more portable (works with any bourne shell, not just bash and zsh).

Comment by inof 362 weeks and 2 days ago


The point is to show the use of the "

Sure, echo is an alternative but it means you have to use a pipe.

I am here on commandlinefu to learn *new* things.

Comment by mpb 362 weeks and 2 days ago

eh? that's odd: what happened to the three less-than symbols in my previous comment? Some odd character handing in the text input box for commandlinefu?

It would also be nice to be able to edit comments (eg for spelling correctione etc).

Comment by mpb 362 weeks and 2 days ago

What is the "three less-thans" operation actually called? I can't figure it out, and it's not in the TLDP guide!

Comment by chriszuma 226 weeks and 4 days ago

The "three-less-thans" operator is called a Here String in the bash man page. See also chapter 19.1 of the Advanced Bash-Scripting Guide in the TLDP.

Comment by bobnewstadt 219 weeks ago

Your point of view

You must be signed in to comment.