I use this simple command for remove all backup files generated usually by editors like Vim and Emacs.

Removes an iptables rule created by fail2ban. This example shows how to remove a rule for an IP from the fail2ban-SSH chain. Can be used for any service monitored by fail2ban.

For more on fail2ban, see http://www.fail2ban.org/wiki/index.php/Main_Page

gpg's compression is as suitable as gzip's however your backups can now be encrypted.

to extract use:

remove file that has sensitive info safely. Overwrites it 33 times with zeros

deborphan(1) must be installed.

To decrypt the files replace "ccenrypt" with "ccdecrypt.

ccrypt(1) must be installed. It uses the AES (Rijndael) block cipher.

To make it handier create an alias.

Often I need to edit a bash or perl script I've written. I know it's in my path but I don't feel like typing the whole path (or I don't remember the path).

During this operation :

# mv Joomla_1.5.10-Stable-Full_Package.zip /var/www/joomla/

I invoke /var/www/joomla/ as last command argument. To change in this directory I can use

# cd !$

So I go to

hob:/var/www/joomla#

Assuming that 219,229 and 221 are entries in history, I recall them in a single line for execute multiple commands

219 ifdown wlan0

...

221 ifup wlan0

...

229 iwconfig wlan0 mode Managed

so the result is execution of # ifdown wlan0 ; iwconfig wlan0 mode Managed ; ifup wlan0

tailf same as tail -f follow the flow of a log file, showing it in real time to stdout.

Yeah, there are many ways to do that.

Doing with sed by using a for loop is my favourite, because these are two basic things in all *nix environments. Sed by default does not allow to save the output in the same files so we'll use mv to do that in batch along with the sed.

When you have to manage lot of servers, it's boring to type ssh root@myhost for each connection. Now you can type juste "s someting" and you are connected.

You can too add bash_completion script to complet with tab the name of your servers. This will be the next tips from me ;)

You will need libnotify-bin for this to work:

From time to time one forgets either thier gpg key or other passphrases. This can be very problematic in most cases. But luckily there's this script. Its based off of pwsafe which is a unix commandline program that manages encrypted password databases. For more info on pwsafe visit, http://nsd.dyndns.org/pwsafe/.

What this script does is it will help you store all your passphrases for later on and allow you to copy it to your clipboard so you can just paste it in, all with one password. Pretty neat no?

You can find future releases of this and many more scripts at The Teachings of Master Denzuko - denzuko.wordpress.com.

With this command you can use shell variables inside sed scripts.

This is useful if the script MUST remain in an external file, otherwise you can simply use an inline -e argument to sed.

bash.org is a collection of funny quotes from IRC.

WARNING: some of the quotes contain "adult" jokes... may be embarrassing if your boss sees them...

Thanks to Chen for the idea and initial version!

This script downloads a page with random quotes, filters the html to retrieve just one liners quotes and outputs the first one.

Just barely under the required 255 chars :)

Improvment:

You can replace the head -1 at the end by:

which will separate the quotes with a "%" and place it in the file.

and then:

which will make the file ready for the fortune command

and then you can:

which will give you a random quote from those in the downloaded file.

I download a file periodically and then use the fortune in .bashrc so I see a funny quote every time I open a terminal.

See all fonts installed in your system

This is a bit to bit copy so if you have a 500GB hard disk it will take a long time even if have Gigabit Ethernet

This opens up nautilus in the current directory, which is useful for some quick file management that isn't efficiently done from a terminal.

Find all corrupted jpeg in the current directory, find a file with the same name in a source directory hierarchy and copy it over the corrupted jpeg file.

Convenient to run on a large bunch of jpeg files copied from an unsure medium.

Needs the jpeginfo tool, found in the jpeginfo package (on debian at least).