apart from not being generalisable to all shells, `Y <<< X` seems nicer to me than `echo X | Y`, e.g.

it reads easier, you type less, and it also looks cool

this exits bash without saving the history. unlike explicitly disabling the history in some way, this works anywhere, and it works if you decide *after* issuing the command you don't want logged, that you don't want it logged

... $$ ( or ${$} ) is the pid of the current bash instance

this also works perfectly in shells that don't have $$ if you do something like

Some commands (such as netcat) have a port option but how can you know which ports are unused?

A quick way to list services running

Python comments begin with a #. Modify to suit other languages.

Other uses: Instead of m0 use m$ for end of file or d for deleting all comments.

This command will replace all instances of 'foo' with 'bar' in all files in the current working directory and any sub-directories.

This command will replace all instances of 'foo' with 'bar' in all files in the current working directory.

This turns your iptables packet filter to a "Allow any from any to any" filter, so you can rule out any filtering issues when you have a problem to enable a connection from or to your host.

To re-enable it, run /etc/init.d/iptables restart

You can watch channels of your freebox, everywhere. With " vlc http://your-ip:12345 " on the client and ncurses vlc interface on the host. et voila

Change files case, without modify directories, recursively.

... fucking vfat

Extensible to other ugly extensions like *.JPG, *.Jpg etc..

Leave out the last pipe to sh to perform a dry run.

To resize photos without changing exif datas, pretty cool for gps tagging.

(Require ImageMagick)

This is useful for sending data between 2 computers that you have shell access to. Uses tar compression during transfer. Files are compressed & uncompressed automatically. Note the trailing dash on the listening side that makes netcat listen to stdin for data.

on the listening side:

explanation: open netcat to -l listen on -p port 2022, take the data stream and pipe to tar -x extract, -v verbose, -f using file filename - means "stdin"

on the sending side:

explanation: compress all files in current dir using tar -c create, -v verbose, -f using file, - filename - here means "stdout" because we're tar -c instead of tar -x, -w3 wait 3 seconds on stream termination and then end the connection to the listening host name_of_listening_host, on port 2022

Allows you to save progress without committing.

To revert to an undo point, svn revert then apply the undo point with patch.

Similar: http://www.commandlinefu.com/commands/view/373/archive-all-files-containing-local-changes-svn

The above was done using the i386 flashplayer plugin, and was installed on a AMD64 machine running an AMD64 kernel and AMD64 programs. the resulting plugin install ultimately didn't work for swiftfox (but worked for iceweasel) without also covering it with a nspluginwrapper which took a bit of fenangaling to get to work (lots of apt-getting) but it is a nice feature to be able to trick installers that think you need i386 into running on a amd64, or at least attempting to run on amd64. Enjoy

If you put this in your .bashrc, you might also want to add this to make it use the colors by default:

This is useful for piping to other commands, as well:

I got really tired of having tree always show me tons of .svn and .git stuff that I don't care about. With this alias, "tree" uses pretty colors, snazzy line graphics, and ignores any source control and package mumbojumbo. (Customize the *.*.package glob, of course.)

Good old cat & output redirection. Using this method you can combine all kinds of things - even mpeg files. My video camera makes a series of .mpeg files that are broken into 4gb chunks. Using this command I can easily join them together. Even better, combined with the cp command the files can be copied and joined in one step.

I wrote a script called bootstrap.py to delete the database, then load a new database with initial values. With this single-line shell loop, when I need to make a schema change (which happens often in the early stages of some projects), I hit ctrl-C to stop the running Django server, then watch bootstrap.py do its thing, then watch the server restart.

This is useful if you have a collection of files in folders (for example, a bunch of .zip files that are contained in folders) and you want to move them all to a common folder.