All commands (14,187)

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. 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.

Share Your Commands


Check These Out

Watch several log files in a single window
It works like a "tail -f" on several files. Use the number keys 0-9 to set a baseline in the numbered window. Pressing "b" let you scroll back in one of the windows.

One command line web server on port 80 using nc (netcat)
Very simple web server listening on port 80 will serve index.html file or whatever file you like pointing your browser at http://your-IP-address/index.html for example. If your web server is down for maintenance and you'd like to inform your visitors about it, quickly and easily, you just have to put into the index.html file the right HTML code and you are done! Of course you need to be root to run the command using port 80.

Remove all unused kernels with apt-get
Remove old kernels (*-generic and *-generic-pae) via apt-get on debian/ubuntu based systems. Tested on ubuntu 10.04 - 12.04.

Graphical tree of sub-directories with files
The command finds every item within the directory and edits the output so that subdirectories are and files are output much like the tree command

Perpetual calendar
Gets any date since today. Other examples of recognized expressions are "2 years 4 days ago", "7 months" (in the future), "next Sunday", "yesterday", "tomorrow", etc.

tar the current directory wihtout the absolute path
tars the current directory (and its children) in an archive of the same name (plus ".tar" :)) in the parent directory without the absolute path, so that when the archive is extracted, only the current directory name is created for the path. Assumes bash/zsh.

Insert commas to make reading numbers easier in the output of ls
This modifies the output of ls so that the file size has commas every three digits. It makes room for the commas by destructively eating any characters to the left of the size, which is probably okay since that's just the "group".   Note that I did not write this, I merely cleaned it up and shortened it with extended regular expressions. The original shell script, entitled "sl", came with this description:    : '  : For tired eyes (sigh), do an ls -lF plus whatever other flags you give  : but expand the file size with commas every 3 digits. Really helps me  : distinguish megabytes from hundreds of kbytes...  :  : Corey Satten, corey@cac.washington.edu, 11/8/89  : '   Of course, some may suggest that fancy new "human friendly" options, like "ls -Shrl", have made Corey's script obsolete. They are probably right. Yet, at times, still I find it handy. The new-fangled "human-readable" numbers can be annoying when I have to glance at the letter at the end to figure out what order of magnitude is even being talked about. (There's a big difference between 386M and 386P!). But with this nifty script, the number itself acts like a histogram, a quick visual indicator of "bigness" for tired eyes. :-)

Generate Sha1, MD5 hash using echo
This is mostly for my own notes but this command will compute a md5 message digest from the command line. You can also replace md5sum with other checksum commands (e.g., sha1sum)

list files recursively by size

List your interfaces and MAC addresses
Requires sysfs mounted on /sys - may only be useful for Linux systems. Could also use "printf '%-8s %s\n' $(basename $f) $(cat $f/address)" instead of echo.


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: