Automated Mail Purging for SMTP Mail
Copy the scripts to your favorite directory. I used /usr/local/bin. Edit mailrm.sh and mailage.sh to reflect your mail directory and the location of formail. Then just run the script with the number of days to retain messages as its argument. For example, to purge messages older than 60 days:
Is this mail purge solution perfect? No, it does nothing to lock mail files, which could pose a problem if a user's mail client polls frequently or this job runs during busy hours. Some possible steps to address this could include stopping sendmail while the scripts run, preventing the POP3 server from running and tightening permissions on the mail directory to prevent access from non-superusers. Since it would normally run in the early-morning hours via cron, the probability of collision would be low.
Also, this solution relies on external utilities that may not function as expected. formail might not properly handle all the mail headers, though I haven't encountered problems yet. cat might not like some characters that could appear in messages, resulting in lost message text. I've had few problems with cat, but your experience may be different.
The date conversion logic in maildate.sh is simplistic. It's not accurate for the year 1900, and the leap year calculation will not work correctly after the year 2099. However, it works well for calculating the difference between two dates, and it's reasonably fast.
Since I use three scripts to get around parameter-passing limitations in Bash, this package runs more slowly than it might (because of having to fork processes repeatedly). Recoding the scripts into a single Perl script might help—my Perl skills are too limited for this project.
If you have a need for automated mail purging, these scripts can help you reach your goal. At least, they may give you ideas for your own solution. If you create a more elegant solution, I'd like to hear about it.
All listings referred to in this article are available by anonymous download in the file ftp://ftp.linuxjournal.com/lj/listings/issue47/2118.tgz.
Michael S. Keller (firstname.lastname@example.org) is a Technical Analyst with Paranet, Inc., a nation-wide network services provider owned by Sprint. He has used computers for twenty years and Unix variants for seven. Paranet's virtual home is at http://www.paranet.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
- SUSE LLC's SUSE Manager
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- Tech Tip: Really Simple HTTP Server with Python
- Google's SwiftShader Released
- Parsing an RSS News Feed with a Bash Script
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