September 08, 2009

More linuxy stuff

Two new how-to items and an update:

Back in my Brown CS days I was converted to the One True Way of keyboards: Sun keyboards put keys you use more often closer to where your fingers already are, decreasing stress. What's not to like? But even Sun makes its keyboards to follow the PC standard these days, so you have to remap them. Easier on a Linux box than on other systems---just use xmodmap---but I had a strange behaviour whereby remapping the backspace key to be backslash (unshifted) or the pipe/vertical bar symbol (shifted) does remap both, but it remaps them both to the backslash. Mysterious. Googling on this, along with keywords like "Ubuntu" and "Jaunty", kept turning up ways to turn off a crazy behaviour whereby shift+backspace caused the X server to reset. But that's not what mine did! Even without the xmodmap, shift+backspace just did a simple backspace. Although, its xmodmap entry did read "BackSpace Terminate_Server"....

So here's what I think happened. The people that put together the default keyboard mapping packages had "helpfully" bound Shift+Backspace to terminate the server, which is terrible. The people that put together the keyboard drivers couldn't fix it the right way (by changing the key map), but were sick of the complaining, so they worked around it by making the keyboard driver remap Shift+Key22 to only send Key22, so that the next layer never even saw the shift key. What a mess. And it appears to even be upstream of Ubuntu; I saw a Debian machine exhibit the same rebinding behaviour.

Anyway, I finally found the fix in a post helpfully titled "Getting a pipe ("|") character with Shift-BackSpace key-combo" on the forums: you have to (as root) the file /usr/share/X11/xkb/symbols/pc and in the BKSP entry, change the type from CTRL+ALT to TWO_LEVEL. Then the xmodmap can proceed as expected.

Then today, I was trying to migrate my on-campus wiki over to the new machine. Since I hadn't played with it since I first followed the MediaWiki install instructions a year ago, I had forgotten a lot, and so I found a terse post on the subject to be very helpful... but not perfectly. What to do on the old server is correct:

 mysqldump -u root -p wikidb > wikidb.sql

 tar -cvf wiki.tar wiki ;this is the wiki folder on document root
but what to do on the new server is incomplete. Yes, you need to copy over and untar all the wiki files, but what about the database? I ran into two snags. First, the default MySQL install was not letting me in, giving me an "Access denied" error, either as root or myself, with any of my passwords. I still don't know what exactly cause it, but another post got me out of it, although even there it forgot to say to shut down the running mysqld first (e.g. with /etc/init.d/mysql stop). After the root password is reset, you can then restart the daemon and connect as described. What then? You want to connect to the wiki database and source the dump file you created.
$ mysql -u root -p wikidb
Password: ******
> source wikidb.sql
Now everything's loaded, and there's one last thing (probably): you'll have to configure Apache or your local httpd to handle short URLs as described in the MediaWiki manual page on the subject. Whew!

Finally, an update on gizmod: it doesn't seem to do what I want. In order to capture keyboard shortcuts and translate them into other keyboard combos without also sending the original combo, you need to grab exclusive control of the device, which although they claim to support it doesn't seem to work correctly. Too bad.

"While many people who use the Web regularly feel pretty confident with it, we all know someone---someone close---who can never quite figure out whether or not the one-click purchase they just made on is going to ship to the new house or the old one." --Robert Hoekman, Jr.

Posted by blahedo at 8:29pm on 8 Sep 2009
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