Commands by jeffskinnerbox (4)

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Use xdg-open to avoid hard coding browser commands
I rarely use the system menu to start applications. I use keyboard shortcuts instead. Keyboard shortcuts are convenient time savers. To configure the shortcuts I use gconf-editor or CompizConfig Settings Manager (if I have Compiz turned on). Lately I've been using Chromium as my browser. Since Chromium is under heavy development it occasionally becomes unusable and I have to switch back to Firefox. I was hard-coding the browser command in my keyboard shortcuts. This became problematic with frequent browser hopping. I now use the xdg-open command when defining my keyboard shortcuts. xdg-open opens a file or URL in the user's preferred application. In the metacity keybinging_commands I have xdg-open http://gmail.com where I used to have firefox http://gmail.com. Now when switching browsers I don't have to update each keyboard binding command I just change my default browser in Ubuntu by clicking through the menu: System / Preferences / Preferred Applications / Web Browser. xdg-open is more convenient for this browser hopper.

find all active IP addresses in a network
There are several other options. This one is plain and simple. Another option is: nmap -sP 192.168.0.0/24

add a ip address to a network device
Allows to add more than one ip address to one network device.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Super Speedy Hexadecimal or Octal Calculations and Conversions to Decimal.
^Hexadecimal Ten minus Octal Ten is Eight(in Decimal). $ echo "$(( 0xaf )) = $(( 0257 ))" ^Hexadecimal AF and Octal 257 are both Decimal 175.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Edit a PDF's metadata using exiftool
Edit the pdf file foo.pdf's metadata. -overwrite_original overwrites the original file (w/o it exiftool creates a new file)

Disable sleep mode via cli and systemd (Centos, Debian Ubuntu?)
This causes computer to never power off or go into sleep mode. Disables sleep mode linux.

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

parrallel execution of a command on remote hosts by ssh or rsh or ...
parrallel execution of a command on remote host by ssh or rsh or ... very useful for cluster management (software update)


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