commandlinefu.com is the place to record those command-line gems that you return to again and again.
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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:
Immediately after installing things into your PATH (e.g. under /usr/bin), currently open shells cannot find them ("zsh: command not found"). Use rehash to get the shell to rescan available executables.
Discovering all executables on your system that can be run as another user, especially root, is critical for system security. The above command will find those files with have SUID or SGID bits set and are owned by the root user or group.
Very useful when you need disk space. It calculates the disk usage of all files and dirs (descending them) located at the current directory (including hidden ones). Then sort puts them in order.
Just waste some resources in a philosophical way
To connect to the shell run:
nc server.example.org 2000
Launch a command from within a manpage, vim style. This is rather trivial, but can be very useful to try out the functions described in a manpage without actually quitting it (or switching to another console/screen/...).
Rather than typing out all 10 files, you can use brace expansion to do the trick for you. This is useful for backup files, numbered files, or any files with a repeating pattern. Gives more control than 'rm file*' as I might want to keep others around.
When downloading RPMs from the Internet, you don't have to 'rpm -i' or 'rpm -U' to install the package. Especially, if the package has dependencies. If you have YUM setup to access an RPM repository, this command will install the downloaded package, then any dependencies through YUM that it relies on. Very handy on RPM-based systems.
In this case, I'm keeping an eye on /var/log/messages, but of course any file will do. When I'm following a file, I generally don't want to see anything other than what has been added due to the command or service I've executed. This keeps everything clean and tidy for troubleshooting.
Useful to e.g. keep an eye on several logfiles.
It displays, last 15 yum operations (in last operation as first row order) with its dates. Change 15 to any number of operations you need to display or remove "| tac" to see it in reverse order (last operation as last row)
This will play the audio goodness posted up on PlayTweets via twitter right form the ever loving cmdline. You do not even need a twitter account. I hashed this out in a bit of a hurray as the kids need to get to sleep....I will be adding a loop based feature that will play new items as they come in...after what your are listening to is over.
http://twitter.com/playTweets for more info on playtweets
Generated the CPU utilization stats with 5 lines /every 2 seconds.
Needs sysstat package to be installed prior to use sar.
List the files a process is using.
Copy the file with the given .extension at the source file's location. Eliminates the typing of long paths again and again.
Replace all ocurrences in the file.
The g option is to replace more than one occurrence in the same line. Whitout the g option, it only replace the first occurrence in the line.
This is a simple case of recursing through all directories, adding the '.bak' extension to every file. Of course, the 'cp $file $file.bak' could be any code you need to apply to your recursion, including tests, other functions, creating variables, doing math, etc. Simple and clean recursion.
Useful mainly for debugging or troubleshooting an application or system, such as X11, Apache, Bind, DHCP and others. Another useful switch that can be combined with -mmin, -mtime and so forth is -daystart. For example, to find files that were modified in the /etc directory only yesterday:
sudo find /etc -daystart -mtime 1 -type f
Redirect the local port 2000 to the remote port 3000. The same but UDP:
nc -u -l -p 2000 -c "nc -u example.org 3000"
It may be used to "convert" TCP client to UDP server (or viceversa):
nc -l -p 2000 -c "nc -u example.org 3000"
It allows customizing by means of lesspipe. You need to write a ~/.lessfilter script and put this into your ~/.bashrc: