Commands using sed (1,319)

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Shows users and 'virtual users' on your a unix-type system
Shows a list of users that currently running processes are executing as. YMMV regarding ps and it's many variants. For example, you might need: $ ps -axgu | cut -f1 -d' ' | sort -u

check open ports without netstat or lsof

Print out your hard drive to a jet-direct compatible printer.
Where 192.168.1.2 is a printer with jet-direct. No, I don't suggest this as a backup method.

Create a backup of the file.
It will create a backup of the filename. The advantage is that if you list the folder the backups will be sorted by date. The command works on any unix in bash.

Processor / memory bandwidthd? in GB/s
Read 32GB zero's and throw them away. How fast is your system?

Resize an image to at least a specific resolution
This command will resize an image (keeping the aspect ratio) to a specific resolution, meaning the resulting image will never be smaller than this resolution. For example, if we have a 2048x1000 image, the output would be 1229x600, not 1024x600 or 1024x500. Same thing for the height, if the image is 2000x1200, the output would be 1024x614.

Matrix Style
Another wall matrix :)

Turn On/Off Keyboard LEDs via commandline
Usefull as a light blink to remember events, mails, intrusions, etc... yet another output Since nobody ever uses the scroll lock function... Usefull to interface a linux system with some hardware, for example, opto interfacing the keyboard led to a relay to remotely reset, etc. ( a simple LDR glued over the LED will do the trick ) xset led 3 turns on the third led, ie, Scroll lock xset -led 3 turns it off xset led 1 turns on Numerical Lock led ( doesn t work on all computer ) xset led 2 turns on Caps Lock led ( idem ) Using it as a reset watchdog, the relay expected light pulses. Shall the computer hangs, the relay releases and reset the machine ( discharge of a capacitor ) ;-)

prevent large files from being cached in memory (backups!)
We all know... $ nice -n19 for low CPU priority.   $ ionice -c3 for low I/O priority.   nocache can be useful in related scenarios, when we operate on very large files just a single time, e.g. a backup job. It advises the kernel that no caching is required for the involved files, so our current file cache is not erased, potentially decreasing performance on other, more typical file I/O, e.g. on a desktop.   http://askubuntu.com/questions/122857 https://github.com/Feh/nocache http://packages.debian.org/search?keywords=nocache http://packages.ubuntu.com/search?keywords=nocache   To undo caching of a single file in hindsight, you can do $ cachedel   To check the cache status of a file, do $ cachestats


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