Articles

A Prisoner of Windows (Part 1): We who use Linux desktops sometimes forget that most of our peers do not have our luxuries. At times, we find ourselves forced to devolve, and use a Windows desktop to do our work. When we do, we pine for the vast variety of tools we had under Linux and curse the clumsiness of the software prison that we are locked into.

But, there is hope for us prisoners of Windows. If our Microsoft Windows environment is network-enabled and if we can connect to a suitably configured network-enabled Linux box, we can still work on our platform of choice. So, how do we free ourselves? We give ourselves secure remote access to Linux, both at the command line and at the GUI level with a combination of standard Linux tools and a couple of Open Source applications for Windows.

This article was written by Lew Pitcher and originally published in The Linux Gazette, Issue 129
A Prisoner of Windows Part 2: Pane Relief: When we last met, we had freed our prisoner of Windows so that all the commandline and GUI facilities of a remote Linux system were available to him. But, while our prisoner of Windows is now free to wander the Linux world, he is still bothered by a discontinuity; our Windows user still has the headache of having to manually enter his userid and password into every Linux box he has access to, and he must log directly on to his Linux system to run Linux-based applications.

Well, I have a simple prescription that can cure that syndrome. With a small change to the user's Linux configuration and a few simple Windows tools, we can relieve our Windows user of his "pane" and give him Windows desktop icon access to his Linux-based applications.
Spam? What Spam?: I get a lot of email; mostly spam. Fortunately, my email setup includes procmail and SpamAssassin, so I don't actually see any of that spam email. In conjunction with SpamAssassin, my procmail rules move all emails that fit the criteria for spam, and other abusive messages into a "Spam" mbox file, and I never have to see them. These captured messages are later fed into SpamAssassin's sa-learn to reinforce the Baysean spam filtering system, and then are discarded, unread.

Hints and Tips

Procmail Recipe: One Address, Multiple Users: A while back, I switched ISPs and lost the multiple email addresses that the old ISP provided. With the new ISP, my partner and I were restricted to sharing a single public email address. With fetchmail, I could retrieve our email from my ISP's POP3 server and store it in my lan server for on-demand "offline" reading, but with one email address, either my partner and I had to read each other's mail, or one of us got no mail at all.

I fixed this little problem with the judicious use of a procmail recipe that uses a feature of email addresses to seperate mail destined for my partner from mail destined for me.
Validating Web-based logons with FTP: As part of a PHP web app I developed, I needed to authenticate the web client user with a remote system. Unfortunately, this system is a mainframe and setting up a web-enabled authentication product on it is somewhat timeconsuming and requires a lot of administrivia. I wanted to avoid all that, so I had to come up with another way to authenticate web users remotely.
Quick and Dirty GUI Calendar: A while back, I needed a yearly calendar for my X desktop. Since, at the time, I ran a desktop that did not include an integrated Calendaring facility, I couldn't just click on something. So, I built a GUI perpetual calendar, in a shell script.
Cleaning Up: With my desktop machine's last system upgrade, I changed how I managed my /tmp directory. Before the upgrade, my configuration mounted a tmpfs on /tmp at startup, but now, it mounts a separate ext2 partition for /tmp. Linux implements the tmpfs filesystemtype in swap, making the contents of the directory really temporary; files and directories in such a filesystem vanish on reboot. But, now with the ext2 filesystem, /tmp files and directories stick around. This means that I now needed something to clean up my /tmp directory on a regular basis. So, I wrote a short script to do just that.
The Difference between Softlinks and Hardlinks: Someone posted this question to one of the Linux newsgroups I follow:

Can someone give me a simple explanation of the difference between a soft link and a hard link? The documentation I've read mention these links but make no strong explanations of their meaning and how/when to use them. Thanks!

Here's how I explained the differences.
Uninterruptable Sleep: Another question from usenet read:

I have read that no program can ignore SIGKILL and SIGSTOP. But, a task is in UNINTERRUPTIBLE state when it sleeps blocking all signals. Could someone help me understand the scenario? Isn't it blocking all signals (including SIGKILL and SIGSTOP)?