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





Commands tagged tee from sorted by
Terminal - Commands tagged tee - 31 results
dd if=/dev/sda | tee >(dd of=/dev/sdb) | dd of=/dev/sdc
2009-12-11 17:34:38
User: nerd65536
Functions: dd tee
Tags: bash tee dd pipe root

If you have some drive imaging to do, you can boot into any liveCD and use a commodity machine. The drives will be written in parallel.

To improve efficiency, specify a larger block size in dd:

dd if=/dev/sda bs=64k | tee >(dd of=/dev/sdb bs=64k) | dd of=/dev/sdc bs=64k

To image more drives , insert them as additional arguments to tee:

dd if=/dev/sda | tee >(dd of=/dev/sdb) >(dd of=/dev/sdc) >(dd of=/dev/sdd) | dd of=/dev/sde
cat /path/to/some/file.txt | tee /dev/pts/0 | wc -l
2009-11-07 22:24:28
User: atoponce
Functions: cat tee wc
Tags: tee

This is a cool trick to view the contents of the file on /dev/pts/0 (or whatever terminal you're using), and also send the contents of that file to another program by way of an unnamed pipe. All the while, you've not bothered saving any extra data to disk, like you might be tempted to do with sed or grep to filter output.

bash -x test.sh 2>&1 | tee out.test
2009-09-03 17:10:44
User: arcege
Functions: bash tee

Sends both stdout and stderr to the pipe which captures the data in the file 'out.test' and sends to stdout of tee (likely /dev/tty unless redirected). Works on Bourne, Korn and Bash shells.

echo "Hello World." | tee -a hello.txt
2009-06-26 00:55:59
Functions: echo tee
Tags: tee

When plumbers use pipes, they sometimes need a T-joint. The Unix equivalent to this is 'tee'. The -a flag tells 'tee' to append to the file, rather than clobbering it.

Tested on bash and tcsh.

echo "foo bar" | sudo tee -a /path/to/some/file
2009-02-18 13:54:25
User: raphink
Functions: echo sudo tee

This is the solution to the common mistake made by sudo newbies, since

sudo echo "foo bar" >> /path/to/some/file

does NOT add to the file as root.


sudo echo "foo bar" > /path/to/some/file

should be replaced by

echo "foo bar" | sudo tee /path/to/some/file

And you can add a >/dev/null in the end if you're not interested in the tee stdout :

echo "foo bar" | sudo tee -a /path/to/some/file >/dev/null