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





Join lines

Terminal - Join lines
cat file | tr -d "\n"
2010-12-02 09:22:02
User: uzsolt
Functions: cat file tr
Join lines

This command deletes the "newline" chars, so its output maybe unusable :)


There are 2 alternatives - vote for the best!

Terminal - Alternatives
cat file | tr "\n" " "
2010-12-02 09:21:02
User: uzsolt
Functions: cat file tr

It's works only when you replace '\n' to ONE character.

tr "\n" " " < file
2010-12-08 16:13:54
User: randy909
Functions: tr

Even shorter. Stolen from comment posted by eightmillion.

perl -pe 'eof()||s/\n/<SOMETEXT>/g' file.txt
2010-12-02 01:19:27
User: eightmillion
Functions: perl

This command turns a multi-line file into a single line joined with <SOMETEXT>. To skip blank lines, use:

perl -pe '(eof()||s/^\s*$//)||s/\n/<SOMETEXT>/g' file.txt
awk 'BEGIN{RS="\0"}{gsub(/\n/,"<SOMETEXT>");print}' file.txt
2010-12-12 21:43:22
User: __
Functions: awk

awk version of 7210. Slightly longer, but expanding it to catch blank lines is easier:

awk 'BEGIN{RS="\0"}{gsub(/\n+/,"<SOMETEXT>");print}' file.txt
echo -e "aa\nbb\ncc\ndd\n123" | sed -e :a -e "/$/N; s/\n/;/; ta"

Know a better way?

If you can do better, submit your command here.

Your point of view

You must be signed in to comment.