Hack and / - Lightning Hacks Strike Twice
My laptop doubles as a tablet, and even though I don't use the tablet mode very often, when I do use it, I like to be able to rotate the screen around to portrait mode and back. Now, dock applications exist that can do this with a few clicks, and I always could just try to remember the right xrandr commands, but instead, I wrote a little script that I then bound to one of the hardware buttons on my laptop display. Each time I press the button, it runs the script and rotates the screen another 90 degrees.
The key to the script is to keep track of your current orientation. When xrandr rotates, it rotates only left, right, inverted or normal, so if you already are rotated to the left and rotate left again, it won't change. To accomplish this, I just write the current orientation to a temporary file. Listing 1 shows the full script.
Listing 1. Screen Rotation Script
#!/bin/sh export ORIENTATION=`cat /tmp/.orientation` if [ $ORIENTATION -eq "90" ]; then xrandr --auto xrandr --output LVDS --rotate inverted echo 180 > /tmp/.orientation echo "180" | osd_cat --shadow=2 --align=center \ --pos=bottom --color=green --delay=2 \ --font=lucidasanstypewriter-bold-24 \ --offset 40 & elif [ $ORIENTATION -eq "180" ]; then xrandr --auto xrandr --output LVDS --rotate left echo 270 > /tmp/.orientation echo "270" | osd_cat --shadow=2 --align=center \ --pos=bottom --color=green --delay=2 \ --font=lucidasanstypewriter-bold-24 \ --offset 40 & elif [ $ORIENTATION -eq "270" ]; then xrandr --output LVDS --rotate normal echo "Normal" | osd_cat --shadow=2 --align=center \ --pos=bottom --color=green --delay=2 \ --font=lucidasanstypewriter-bold-24 \ --offset 40 & echo 0 > /tmp/.orientation else xrandr --auto xrandr --output LVDS --rotate right echo 90 > /tmp/.orientation echo "90" | osd_cat --shadow=2 --align=center \ --pos=bottom --color=green --delay=2 \ --font=lucidasanstypewriter-bold-24 \ --offset 40 & fi
Notice in Listing 1 that I also added an echo piped to osd_cat. This is optional and just displays the current orientation on my screen. If you want to use this, be sure you have the osd_cat utility (it's included with the xosd-bin package in Debian and Ubuntu). The way the script is set up, it will run through each of the orientations in order before it goes back to normal. Because the temporary file will be deleted any time the machine reboots, I made sure to set the default mode to rotate 90 degrees.
Kyle Rankin is a Senior Systems Administrator in the San Francisco Bay Area and the author of a number of books, including Knoppix Hacks and Ubuntu Hacks for O'Reilly Media. He is currently the president of the North Bay Linux Users' Group.
Kyle Rankin is a VP of engineering operations at Final, Inc., the author of a number of books including DevOps Troubleshooting and The Official Ubuntu Server Book, and is a columnist for Linux Journal. Follow him @kylerankin.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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