Implementing a deltree Command in Linux
If C library calls do most of the grunt work, writing a simple utility like deltree is neither difficult nor time consuming and may offer unanticipated opportunities to use the framework of the program to address additional problems. This code can be adapted to perform the same functions as find; use it as a skeleton for a findfile command which scans a directory tree for file names matching a command-line argument. Just replace the file and directory deletion subroutines with functions that compare each file name with the target name and print out the path name to each match.
Do you port code from the Borland or Watcom PC DOS or OS/2 environments and move entire directory trees into Linux space at once? If so, then you have probably discovered that unwanted files migrate along with the necessary ones: files with suffixes such as .map, .sym, .dsk, .swp, .prj, .exe, and the like. With modification, deltree can also provide a framework for a cleandir utility that removes the chaff from the toolbox directory tree. To make the necessary changes, replace StrStack with a StrList class which contains a list of target file name suffixes. Instead of removing all files, the utility checks the suffix of each file in the directory tree against the list of target suffixes and deletes selectively. Once you have the hang of walking a Linux directory tree, creating plug-in functions to perform other tasks is a simple matter, and it is easy to generate a group of utilities which address a broader spectrum of directory tree maintenance issues.
All code needed to implement this command is available by anonymous download in the file ftp://ftp.linuxjournal.com/pub/lj/listings/issue52/2439.tgz.
Graydon Ekdahl (email@example.com) s president of Econometrics, Inc. located in Chapel Hill, N.C. Graydon enjoys creating database applications and is interested in data structures, algorithms, C++ and Java.
Practical Task Scheduling Deployment
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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- SUSE LLC's SUSE Manager
- Managing Linux Using Puppet
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- Google's SwiftShader Released
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
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