Jaharmi’s Irreality renewable hyperlinks with 0% transfat since 1999

When you have the print queue window open for a printer in Mac OS X Leopard, the Printer menu > Print Test Page command is active. That command sends the CUPS test page to the selected print queue.

The test page file itself is a PostScript document located at this path:

/usr/share/cups/data/testprint.ps

Since Leopard — like Mac OS X versions since Panther, has a built-in PostScript interpreter — you can open up this PostScript document and have it rendered as a PDF. By default, it will be sent to the Preview application.

It’s helpful to be able to view this document on-screen, so you can see what it is supposed to look like, in case your printer is not working as intended. You can compare the on-screen results with the printed output to verify how well your printer is working.

There can be times when you need to troubleshoot Directory Services in Mac OS X during system starts up. Directory Services apparently sits above and below the kernel — depending on what each of those components needs to do — so having debugging capability early on in the boot process can help you hone in on problems.

To enable debug logging at startup, run the following at the command line:

$ touch /Library/Preferences/DirectoryService/.DSLogDebugAtStart

… and then, on the next restart, debug logging will be enabled. This is equivalent to running:

$ sudo killall -USR1 DirectoryService

… but the advantage is is that debug logging begins at startup, rather than whenever you can log in and start it manually.

Remove the file from the path above when you want to disable the logging for the subsequent restart. As a file whose name starts with a dot, you won’t see it listed by default in the Finder. (The Finder hides dot files by default.)

$ rm /Library/Preferences/DirectoryService/.DSLogDebugAtStart

If you want to search the mailing list archives for the MacEnterprise.org list with LaunchBar’s Search Templates feature, add the following to your LaunchBar configuration:

http://lists.psu.edu/cgi-bin/wa?S2=MACENTERPRISE&q=*&s=&f=&a=&b=

I added it in my personal search templates for UTF-8, named it “MacEnterprise list archives,” and saved it in my LaunchBar configuration. This makes it much faster to find topics that have appeared on the MacE list, because they are a few keystrokes away. LaunchBar substitutes your encoded search terms for the asterisk after the “&q=” text, and that’s where the magic lies.

The Lullabot Web site has a clever way to help answer the question of “Is that site running Drupal?” Angie Byron mentions that the HTTP “Expires” header returned by Drupal corresponds to a specific default date. Look for that date in the HTTP headers, and you can make a reasonable guess that a site is a Drupal site — or at least one that hasn’t modified one of the core files.

Some commenters posted notes about how to do the same thing with wget and then curl. I expanded on the curl instructions to make them a little more robust (especially in the case of redirects or URL rewriting), and here’s the result:

$ curl -fsIL http://jaharmi.com/ 2>&1 | grep -q -m 1 "Expires: Sun, 19 Nov 1978 05:00:00 GMT" && echo "Yes, this appears to be a Drupal site." || echo "No, this does not appear to be a Drupal site."
Yes, this appears to be a Drupal site.

In trying to determine the age of the command file on a Radmind client — in this case, a Mac OS X 10.5 Leopard system — I learned that its modification date is the same as on the server. This is true on multiple clients I examined, so I believe it to be both consistent and intentional. It also makes sense.

What timestamp, then, can you use to determine how old your command file is, or when your client last updated?

Let’s look into this. For example, here is the command file on a client:

[RadmindClientA]$ ls -ul /private/var/radmind/client | grep command.K
-rw-r--r-- 1 root wheel 667 Jun 3 05:30 command.K
[RadmindClientA]$ ls -cl /private/var/radmind/client | grep command.K
-rw-r--r-- 1 root wheel 667 May 29 10:28 command.K
[RadmindClientA]$ ls -l /private/var/radmind/client | grep command.K
-rw-r--r-- 1 root wheel 667 May 29 10:21 command.K

And the same file examined on the server:

[RadmindServer]$ ls -ul /private/var/radmind/command | grep selected-client-command.K
-rw-r----- 1 root wheel 667 Jun 3 05:27 selected-client-command.K
[RadmindServer]$ ls -cl /private/var/radmind/command | grep selected-client-command.K
-rw-r----- 1 root wheel 667 May 29 10:21 selected-client-command.K
[RadmindServer]$ ls -l /private/var/radmind/command | grep selected-client-command.K
-rw-r----- 1 root wheel 667 May 29 10:21 selected-client-command.K

The status change time (ls -cl) is a little bit harder to understand. I’ve seen it minutes apart from the modification time on a client, but it is the same as the modification time when viewed on the server.

The access time (ls -ul) of the command file on the client, however, simply corresponds to when ktcheck last ran.

For good measure, another client:

[RadmindClientB]$ ls -ul /private/var/radmind/client/ | grep command.K
-rw-r--r-- 1 root wheel 1188 Jun 5 05:08 command.K
[RadmindClientB]$ ls -cl /private/var/radmind/client/ | grep command.K
-rw-r--r-- 1 root wheel 1188 Jun 3 14:13 command.K
[RadmindClientB]$ ls -l /private/var/radmind/client/ | grep command.K
-rw-r--r-- 1 root wheel 1188 Jun 3 14:09 command.K

And its command file on the server:

[RadmindServer]$ ls -ul /private/var/radmind/command | grep another-selected-client-command.K
-rw-r--r-- 1 root wheel 1188 Jun 4 05:13 another-selected-client-command.K
[RadmindServer]$ ls -cl /private/var/radmind/command | grep another-selected-client-command.K
-rw-r--r-- 1 root wheel 1188 Jun 3 14:09 another-selected-client-command.K
[RadmindServer]$ ls -l /private/var/radmind/command | grep another-selected-client-command.K
-rw-r--r-- 1 root wheel 1188 Jun 3 14:09 another-selected-client-command.K

I looked into this because I was wondering why ktcheck -C (to “clean” the /private/var/radmind/client directory) wasn’t having the effect I expected. I thought it cleared out the client directory and started with fresh files, which would all have new timestamps because they were new to the client. When I didn’t get the new timestamps I anticipated, I worked through what I saw until I settled on this explanation.

The result? The main means you have of determining whether the command file has been updated is its access time. The access timestamp corresponds with the date and time of the last ktcheck action. This appears to be the case no matter which flags I’ve used with ktcheck — even with ktcheck -n (where “no files are modified”).

The modification time, for all intents and purposes, only indicates when the file was last changed on the server. Testing this out — with command files that have been overwritten with the exact same contents (using cat), as well as command files deleted on the client before ktcheck — I have reached the conclusion that the modification time changes only when the file contents do.

So, I don’t have solid explanations for all of this. But, I’m now armed with the knowledge that the access timestamp is the most important when you’re looking for the age — or at least the last refresh time — of a Radmind client’s command file.

If you can’t remember the specific name of an application, but you often think of it by another name, you can change how it is referred to in your LaunchBar configuration.

I used to do something like this with Microsoft Excel; I’d change its name in the LaunchBar configuration to “XL.” You could also refer “Lineform” as “Illustrator” without changing the application’s name in the Finder.

To make the change, open LaunchBar. If you can remember the application, perform a search for it. When it is selected in the LaunchBar bar, choose Configuration > Reveal in Configuration. Enter a new name for the selected app in the “Name” column in the window that appears.

I’m not aware, however, of a way to have an application to respond to two or more names in LaunchBar. There may be a way; I just don’t know it.

In Leopard, launchd has some options that can tailor your now-working LaunchAgents for specific circumstances. For example, if you want your LaunchAgent to run only when a user has logged in at the Aqua console — rather than SSH or other login sessions — you can use the “LimitLoadToSessionType” key:

<key>LimitLoadToSessionType</key>
<string>Aqua</string>

Note that to find events that have been limited in this way, you must use launchctl’s “-S” flag to specify the session type. Otherwise, launchctl won’t find jobs that are specified for a different kind of session than the current one, as per Levi Brown’s post.

I also found the “LimitLoadToHosts” and “LimitLoadFromHosts” keys when looking this topic up in the launchd.plist man page.

Thanks to James Bucanek for mentioning this on the launchd-dev list.

Drat! I’ve learned that the commands module for Python, which I use, is deprecated and removed in Python according to PEP 3108. That means I can no longer safely call commands.getstatusoutput() anymore. I’ve frequently used this call in the past because it seemed the sanest, easiest way to call for a shell utility and get both its output and return status (for success or error).

I’ll have to find some other way to perform the same function — preferably one that will work on Python 2.3 from Mac OS X Tiger, Python 2.5.1 from Leopard, and future Pythons. The stated replacement for a number of similar modules (including popen2, which frankly kind-of frightened me off with its name) is the subprocess module from PEP 324, but I don’t know if that will work for my purposes.

There are also a bunch of Mac-specific modules being removed. I don’t use any of them right now, but that doesn’t mean they wouldn’t have been useful.

This kind of thing is spirit-crushing to me for some reason. I’m especially annoyed that Python has been around for so long and it is still reorganizing the ways it calls shell commands. Just settle on something! It seems hard to take it seriously as a system administration scripting language when things like this happen.

On the other hand, I love so much of the Python Standard Library, which has afforded me a lot for system administration …

I’m constantly astounded by the breadth of features available in the Python Standard Library. Although the functions I find there are not always easy to grasp, it is almost always worth searching around a bit for a function or method in the standard library before I write my own code to do something someone else has probably had to do before.

Take the “locale” module. It lets you format certain kinds of data based on your locale and its customs. Numbers (including currency) happen to be one of its specialties. Since I had a need to output long numbers whose digits were grouped with commas — which makes them easier to read — and locale.format() does just that. Even better, it’s internationalized and formats them for your system’s own locale.

>>> import locale
>>> a = {'size': 123456789, 'unit': 'bytes'}
>>> print(locale.format("%(size).2f", a, 1))
123456789.00
>>> locale.setlocale(locale.LC_ALL, '') # Set the locale for your system
'en_US.UTF-8'
>>> print(locale.format("%(size).2f", a, 1))
123,456,789.00

In trying to use it in the bundled Python 2.5.1 on Mac OS X Leopard, I noticed that the default for scripts and the interpreter doesn’t format numbers as I expected for my locale. I found that I needed to set a locale to get the expected formatting. To do this, I run locale.setlocale(), as above. I’m not sure if this is required for other Python installations, but it’s worth mentioning.

One difficulty I created for myself was when I tried mixing more into my format string. For example, locale.format() would fail to reformat a number when I added in the string for the unit from my original dictionary:

>>> print(locale.format("%(size).2f %(unit)s", a, 1))
123456789.00 bytes

In retrospect, this makes total sense, but it took Mark looking over my code to discover my error.

The Distutils Python module includes functions to obtain information about the Python installation. This may be useful for system administrators, and it certainly caught my eye when I read about it.

The results below are from Apple’s bundled build of Python 2.5.1 in Mac OS X Leopard. Credit for the comments describing each function comes from the distutils.sysconfig documentation.

>>> import distutils.sysconfig
>>> distutils.sysconfig.get_python_version() # Get the major Python version without patchlevel
'2.5'
>>> distutils.sysconfig.get_python_lib(standard_lib=True) # Return the directory containing the Python library; if 'standard_lib' is true, return the directory containing standard Python library modules
'/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5'
>>> distutils.sysconfig.get_python_lib() # Otherwise, return the directory for site-specific modules
'/Library/Python/2.5/site-packages'
>>> distutils.sysconfig.get_python_lib(plat_specific=True) # Return any platform-specific modules from a non-pure-Python module distribution
'/Library/Python/2.5/site-packages'

You’d install your own modules for system-wide use in the directory returned by distutils.sysconfig.get_python_lib().