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/
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.
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.
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:
Useful when you've produced a large file of numbers, and want to quickly see the distribution. The value of y halfway along the x axis is the median. Simple!
Just create the listOfNumbers.txt file with a number on each line to try it out.
G option cause a file to be spacing line by line.
Using mplayer's mencoder, you can merge video files together.
'-oac' specifies the audio encoding (here copy, to just copy and not compress)
'-ovc' specifies the video encoding (same thing).
The symlinks command can show status of all symbolic links, including which links are dangling, which symlinks point to files on other file systems, which symlinks use ../ more than necessary, which symlinks are messy (e.g. having too many slashes or dots), etc. Other useful things it can do include removing all dangling links (-d) and converting absolute links to relative links (-c). The path given must be an absolute path (which is why I used $(pwd) in the example command).
Most of you are probably familiar with the "apropos" command for searching man pages. However, did you know there's a similar command inside of gdb? If, for example, you wanted to know all gdb commands that related to threads, you could type "apropos thread". Type "help some_command" to receive more information about a command. Type "help" by itself to see a list of help topics.
An easy one but nice to keep in mind.
Does life get much easier? Read up about wodim for an understanding of its origins in relation to the older `cdrecord` utility
This command looks for a single file named emails.txt which is located somewhere in my home directory and cd to that directory. This command is especially helpful when the file is burried deep in the directory structure. I tested it against the bash shells in Xubuntu 8.10 and Mac OS X Leopard 10.5.6
Umask is obtained subtracting 7 from each cypher of octal format. I store octal perm format in an array,then for each element of array I subtract 7. The result is the umask.
Clone a partion with tar.
I'm sure almost everybody knows this by now. This command will pull the password for the admin login of any plesk machine.
I use this for connect via sftp to a server listening on a non default ssh port.
The socket.gethostname() call returns the host name of the computer. The socket.gethostbyname_ex() call returns a list of three items: The host name, the list of aliases for this host, and a list of IP addresses. Recall that Python?s array starts with index 0, the socket.gethostbyname_ex(?) expression refers to the list of IP addresses. Finally, the print statement prints out the IP addresses, one per line.
Shred can be used to shred a given partition or an complete disk. This should insure that not data is left on your disk
Ok so it's rellay useless line and I sorry for that, furthermore that's nothing optimized at all...
At the beginning I didn't managed by using netstat -p to print out which process was handling that open port 4444, I realize at the end I was not root and security restrictions applied ;p
It's nevertheless a (good ?) way to see how ps(tree) works, as it acts exactly the same way by reading in /proc
So for a specific port, this line returns the calling command line of every thread that handle the associated socket
ifstat, part of ifstat package, is a tool for displaying bandwidth and other statistics. The -n option avoid to display header periodically, the -t option put a timestamp at the beginning of the line.
Works for me on Debian and CentOS
Change your wallpaper every thirty minutes (or however long you like, I suppose) to a randomly selected image in a directory and subdirectories. Bear in mind this is not safe to use if anyone else has write access to your image directory.
Shows the UUID of a filesystem or partition that can be used in kernel root options and in fstab.
Run it without the -u option to generate more information. eg:
~/ sudo vol_id /dev/sda2
Simply changes the wallpaper of xfce4 from the command line. Not for multiple displays.
This works just like write or wall ... cept one thing the sender is anonymous ... if you really want to drive everyone insane replace echo \"The Matrix has you...\" with cat /dev/urandom
nice one to do on April fool's day
use today's time stamp to make a unique directory for today or an hour ago ...
If histappend options is set in bash, the file .bash_history will not be overwrite and history list is append to it.
Also with optional message:
echo "no login for you" > /etc/nologin
(This doesn't affect your current X session - you're already logged in!)