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Split a large file, without wasting disk space
It's common to want to split up large files and the usual method is to use split(1). If you have a 10GiB file, you'll need 10GiB of free space. Then the OS has to read 10GiB and write 10GiB (usually on the same filesystem). This takes AGES. . The command uses a set of loop block devices to create fake chunks, but without making any changes to the file. This means the file splitting is nearly instantaneous. The example creates a 1GiB file, then splits it into 16 x 64MiB chunks (/dev/loop0 .. loop15). . Note: This isn't a drop-in replacement for using split. The results are block devices. tar and zip won't do what you expect when given block devices. . These commands will work: $ hexdump /dev/loop4 . $ gzip -9 < /dev/loop6 > part6.gz . $ cat /dev/loop10 > /media/usb/part10.bin

Beep siren
Infinitely plays beeps with sinusoidally changing sound frequency. Ideal for alarm on an event.

find and reduce 8x parallel the size of JPG images without loosing quality via jpegoptim

Phrack 66 is out, but the .tar.gz is not there yet on phrack.org's website
Nice reading in the morning on the way to work, but sadly the .tar.gz for the whole issue 66 is not on phrack's website yet. So use wget to download.

Redirecting bash output into any X Window
bash output is inserted into the clipboard, then mousepad is started and the clipboard content is pasted. xsel and xdotool needs to be installed. Instead of the mousepad any other editor can be used. I've successfully tested the Sublime Text Editor and it opens a new tab for each new paste. Check Sample output for a usage example. This command is originated from here - http://goo.gl/0q9UT4

Get the IP of the host your coming from when logged in remotely
Even faster without the need for cut... :)

Check apache config syntax and restart or edit the file
Checks the apache configuration syntax, if is OK then restart the service otherwise opens the configuration file with VIM on the line where the configuration fails.

Displays the number of unread messages on your gmail at the top right corner of your terminal
Checks your gmail account every 30 seconds and display the number of new messages in the top right corner of the terminal. A kind of CLI "Gmail notifier" if you will. :-) This is a mashup of http://www.commandlinefu.com/commands/view/7916/put-a-console-clock-in-top-right-corner and http://www.commandlinefu.com/commands/view/3386/check-your-unread-gmail-from-the-command-line

Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines
A variation of a script I found on this site and then slimmed down to just use awk. It displays all users who have attempted to login to the box and failed using SSH. Pipe it to the sort command to see which usernames have the most failed logins.

move messages directly from one IMAP inbox to another
This one-liner was useful in helping someone I know to get off of MS Exchange. `mailutil` proved to be a much better alternative than `fetchmail` or `getmail` in this case. It quickly moved all mails to the destination server (a simple Dovecot/Maildir setup), with no need to convert back and forth between mbox/maildir on the user's own system.


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