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:



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.

Top Tags



To have only unique lines in a file

Terminal - To have only unique lines in a file
sort file1.txt | uniq > file2.txt
2009-03-14 20:24:06
User: rain
Functions: sort uniq
To have only unique lines in a file


There are 2 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

A simpler one would be to use sort's -u flag:

sort -u file1.txt > file2.txt
Comment by dfego 319 weeks and 1 day ago

uniq f1.txt > f2.txt

Comment by mpb 319 weeks and 1 day ago

@mpb: That won't work; uniq's manpage says:

Note: 'uniq' does not detect repeated lines unless they are adjacent. You may want to sort the input first, or use `sort -u' without `uniq'.

Comment by dfego 319 weeks and 1 day ago

If you want to preserve the original order:

awk '!_[$0]++' infile

Use nawk or /usr/xpg4/bin/awk on Solaris.

Comment by radoulov 319 weeks and 1 day ago

@radoulov: nifty!

Comment by mpb 319 weeks ago

sort -u is better.

Comment by ozymandias 319 weeks ago

Your point of view

You must be signed in to comment.