Useful for analyzing disk usage. If you prefer GUI try http://en.wikipedia.org/wiki/Filelight or http://www.marzocca.net/linux/baobab/

Useful if you f.i. want to block/allow all connections from a certain provider which uses successive netnames for his ip blocks. In this example I used the german Deutsche Telekom which has DTAG-DIAL followed by a number as netname for the dial in pools.

There are - as always ;) - different ways to do this. If you have seq available you can use

or without seq you can use bash brace expansion

or if you like while better than for use something like

and so on.

Only tested on Linux Ubunty Hardy. Works when file names have spaces. The "-maxdepth 2" limits the find search to the current directory and the next one deeper in this example. This was faster on my system because find was searching every directory before the current directory without the -maxdepth option. Almost as fast as locate when used as above. Must use double quotes around pattern to handle spaces in file names. -print0 is used in combination with xargs -0. Those are zeros not "O"s. For xargs, -I is used to replace the following "{}" with the incoming file-list items from find. Echo just prints to the command line what is happening with mv. mv needs "{}" again so it knows what you are moving from. Then end with the move destination. Some other versions may only require one "{}" in the move command and not after the -I, however this is what worked for me on Ubuntu 8.04. Some like to use -type f in the find command to limit the type.

Strangely enough, there is no option --lines=[negative] with tail, like the head's one, so we have to use sed, which is very short and clear, you see.

Strangely more enough, skipping lines at the bottom with sed is not short nor clear. From Sed one liner :

# delete the last 10 lines of a file

$ sed -e :a -e '$d;N;2,10ba' -e 'P;D' # method 1

$ sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2

This starts a very basic X session, with just a simple xterm. You can use this xterm to launch your preferred distant session.

Try also startkde or fluxbox or xfce4-session.

To switch between your two X servers, use CTRL+ALT+F7 and CTRL+ALT+F8.

When you've got a list of numbers each on its row, the ECHO command puts them on a simple line, separated by space. You can then substitute the spaces with an operator. Finally, pipe it to the BC program.

I'm pretty sure everyone has curl and sed, but not everyone has lynx.

apt-get is pretty aggressive when it downloads, potentially hogging the bandwidth of your network. The 25 is in KB, change this to your needs.

Useful when you have some wrong on a server (nfs freeze/ immortal process)

The command could show you all conecctions if you skip "grep ESTABLISHED"

Create a bunch of random files with random binary content. Basically dd dumps randomly from your hard disk to files random-file*.

Query Wikipedia by issuing a DNS query for a TXT record. The TXT record will also include a short URL to the complete corresponding Wikipedia entry.You can also write a little shell script like:

and run it like

were your first option ($1) will be used as search term.

Display the amount of memory used by all the httpd processes. Great in case you are being Slashdoted!

A simple "ls" lists files *and* directories. So we need to "find" the files (type 'f') only.

As "find" is recursive by default we must restrict it to the current directory by adding a maximum depth of "1".

If you should be using the "zsh" then you can use the dot (.) as a globbing qualifier to denote plain files:

zsh> ls *(.) | wc -l

for more info see the zsh's manual on expansion and substitution - "man zshexpn".

works on Linux and Solaris. I think it will work on nearly all *nix-es

The initial version of this command also outputted extra empty lines, so it went like this:

192.168.166.48

127.0.0.1

This happened on Ubuntu, i haven't tested on anything else.

slashdot.org webserver adds an X-Bender or X-Fry HTTP header to every response!

Open a ssh session opened forever, great on laptops losing Internet connectivity when switching WIFI spots.

Due to the recent dynamic update vulnerability with bind, I was forced to dig a little deeper into dig...

Get details about an ISO image , without burning it or mounting it .