Smart (Script-Aided) Browsing
Basically, there are two ways to surf the Net: interactively, with any text or graphical browser, or in batch mode, with a program that copies single pages or whole web sites to your hard drive for later use. Script-aided browsing is that part of client side web scripting that makes your use of the Web more efficient and powerful by merging these two techniques in one of the two following ways.
In the first case, you run, either directly or as a dæmon, a script that downloads a web page, extracts from its source code an interesting URL and terminates, thereupon opening your favourite web browser to the corresponding page. Several examples of this first method, applied to Konqueror, Galeon and Netscape (Mozilla uses the same commands as its cousin) have been already described in my article "Client Side Web Scripting", published in the March 2002 issue of Linux Journal.
The second case, also mentioned in that article, is the opposite of the first. That is, during normal interactive web browsing, you notice an hyperlink pointing to an interesting page, and, from within your browser, you launch a web script that will automatically download that page and perform some more or less complex action on it. This action can be anything you can imagine: download all the images contained in that page, list in a pop-up window all the pages it points to and so on. You are limited only by your scripting skills.
Here's an example: mirror a web page and all the pages it points to. Let's assume that you just discovered some new, interesting program. On its home page, a link points directly to the voluminous subsection of the web site containing the complete user manual, and you want to mirror all of the information on your hard disk. The standard tool for these cases is wget, so we don't need to write a new one. However, how do we launch it directly from the web browser, without opening a terminal window and typing the URL by hand? The rest of this article explains how to automate this operation in Konqueror; the example has been tested with the standard KDE, Konqueror and wget tools that come with Red Hat 7.2.
Write a simple shell script that invokes wget with the -m (mirror) option on the first argument and call it wgetscript.sh (or whatever you want, of course). The content of my script is:
#!/bin/bash /usr/bin/wget -m -L -t 5 -w 5 $1 exit
Put the script in the proper directory (I choose $HOME/bin and make it executable, chmod 755 <filename>.
Following the guidelines in this paragraph of the KDE user guide, www.kde.org/documentation/userguide/adding-programs.html, add the script to the KDE menu. Figure 1 shows what I had to write to accomplish this. The string "mymirror" is the one that actually appears in the menu, and the comment is self-explanatory. The really interesting thing in this picture, i.e., the bit of black magic absolutely essential for the correct working of the whole procedure, is the content of the "Command" box:
Apart from using the complete path to the script, what is important is the %u part; this is what will tell Konqueror to launch the script with the complete URL that we selected as the first argument. Notice also that I checked the Run in terminal option. In this way, a Konsole window will open and run your script, and it will be possible to see what happens.
Now, to use this script from Konqueror, you have to right-click on the link that you want to mirror, (I choose the "Manuals online" link on the Free Software Foundation page for this example), and select the Open with.. option. Konqueror will open the window showed in Figure 2, which will you allow to choose "mymirror".
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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.
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- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
- Parsing an RSS News Feed with a Bash Script
- Google's SwiftShader Released
- Rogue Wave Software's Zend Server
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