Here is a command line to run on your server if you think your server is under attack. It prints our a list of open connections to your server and sorts them by amount.

BSD Version:

This command is useful when you want to install the same packages on another fresh OS install for example. To do that, use:

Update a Mandriva Linux system with any pending updates.

This command needs to be run with root privilege.

Using the "--force" option answers "yes" to any interactive prompts

thus allowing the updates to be left unattended to completion.

NB if there is an update for glibc and/or a new kernel then the system

would need to be rebooted for these to take effect.

A prerequisite for running "urpmi --auto-update" is to have correctly defined

urpmi media sources (which can be done by visiting http://easyurpmi.zarb.org/).

If there are no new updates the the message "Packages are up to date" is shown.

I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root):

Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.

Packages: gmailfs fuse-utils libfuse2 gvfs-fuse

Config files: /etc/gmailfs/gmailfs.conf; ~/.gmailfs.conf (make a copy from the another one)

Unmount:

/etc/fstab (Optional):

none /mount/path/ gmailfs

noauto,user[,username=USERNAME,password=PASSWORD,fsname=VOLUME] 0 0

NOTES:

- The options between [] are optional since they already setuped on the config files.

- The '-p' flag shows a prompt for the password entry.

- It's necessary to add the user to the 'fuse' group. You can do that with:

and

- The volume name is not needed but highly recommended to avoid file corruption. Also choose a non-trivial name.

- Google doesn't approve the use of Gmail account other than e-mail purposes. So, I recommend the creation of a new account for this.

Perform a dns zone transfer (if is allowed on target dns server) and print result.

See: "man pwgen" for full details.

Some Linux distros may not have pwgen included in the base distribution

so you maye have to install it (eg in Mandriva Linux: "urpmi pwgen").

To install a theme use:

You can get the .xpi or .jar file from the versions history on the add-on/theme page.

NOTE: may not work in your system (Debian-based is an example).

Not so useful. Just a cool feature.

The download content part.

NOTE: the '-c' seems to not work very well and the download stuck at 99% sometimes. Just finish wget with no problem. Also, the download may restart after complete. You can also cancel. I don't know if it is a wget or Rapidshare glitch since I don't have problems with Megaupload, for example.

UPDATE: as pointed by roebek the restart glitch can be solved by the "-t 1" option. Thanks a lot.

In order to do that, first you need to save a cookie file with your account info. These commands do it (maybe you need to create the '.cookies' dir before). Also, you need to check the "Direct downloads" option on the Premium Zone >> Settings tab.

You need to do this once (as long you maintain the file or your Rapidshare Premium account).

A great password generation tool. http://www.adel.nursat.kz/apg/

Within vi allow to empty a text file in one shot

The vi key sequence !}command will send the file contents from the cursor

to the next blank line as STDOUT to the command specified

and replace that sequence of file lines with the output of the command.

For example: sorting a block of data - !}sort

The sequence !{command will do the same but "upwards" (from the current position towards the start of the file.

head by default displays first ten lines of its output. Use 'head -nXX' to display the XX largest files

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.