Work the Shell - Displaying Image Directories in Apache, Part III
where I'll set size to the desired thumbnail size—75 in our example script.
I'm also going to add a few counters so we can summarize images displayed versus total files displayed at the end. Just because it's, uh, interesting, right?
Here's the latest version of the loop, and as you might expect, it's getting more complicated as it becomes more sophisticated:
for name in * do if [ ! -z "$(file -b $name|grep 'image data')" ] then imgcount=$(( $imgcount + 1 )) figuresize $name if [ ! -z "$height" ] ; then if [ $height -gt $width ] ; then dimensionlabel="height" else dimensionlabel="width" fi echo "<a href=$name><img src=$name border=0" echo "alt=$name $dimensionlabel=$size" echo "align="absmiddle" />" echo "$name ($height x $width)</a>" else echo "<a href=$name><img src=$name border=0" echo "alt=$name height=$size" echo "align="absmiddle" />" echo "$name</a>" fi else echo "<a href=$name>$name</a><br />" fi echo "<hr />" totcount=$(( $totcount + 1 )) done echo "<i>Displayed $imgcount images out of $totcount entries total.</i>"
The resultant output, which is hopefully more attractive, is shown in Figure 2.
Now that we can normalize these thumbnails in the script (at least for non-JPEG images, due to a limitation in the file command), the next thing to examine is how to display the results with multiple images across, in a grid or table, rather than one per line as we see now. That's a bit more complicated, because it involves yet another counter, but while you're waiting for your next issue of Linux Journal, you might bone up on the basic HTML table tags, because that's what we'll be using. Then, finally, we'll switch to ImageMagick from file, so we can get the dimensions of all image files, not only GIF and PNG files.
Dave Taylor is a 26-year veteran of UNIX, creator of The Elm Mail System, and most recently author of both the best-selling Wicked Cool Shell Scripts and Teach Yourself Unix in 24 Hours, among his 16 technical books. His main Web site is at www.intuitive.com, and he also offers up tech support at AskDaveTaylor.com.
Dave Taylor has been hacking shell scripts for over thirty years. Really. He's the author of the popular "Wicked Cool Shell Scripts" and can be found on Twitter as @DaveTaylor and more generally at www.DaveTaylorOnline.com.
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.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- Stunnel Security for Oracle
- SourceClear Open
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- SUSE LLC's SUSE Manager
- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Google's SwiftShader Released
- Non-Linux FOSS: Caffeine!
- Parsing an RSS News Feed with a Bash Script
- Doing for User Space What We Did for Kernel Space
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide