I am not the first person to think of this idea. My notes seem to think that I originally found the idea on the zsh wiki and I stole the code I started with from hackerific.net.

What are global aliases?

Shell aliases let you condense a long winded and/or hard to remember command down to a short, easy to remember word. Old school shells will only match the alias if it is the first word in the command. zsh lets you take that one step further by allowing you to define aliases that will be substituted no matter where they appear on the command line. These are global aliases.

Here is one of my global aliases that I use all the time:

alias -g G='|& egrep -i'

With this alias defined, these two commands are equivalent:

cat /proc/cpuinfo G cache
cat /proc/cpuinfo |& egrep -i cache

My problem with global aliases

When I look at a command line with a global alias it isn't always entirely clear to me what the command I am about to run is actually going to do. Am I sure my G alias has a -i switch? Does it use |& so that it will also grep stderr?

The existing solution

The handy script at hackerific.net sets things up so that as soon as you hit the space bar after typing the global alias it is automatically expanded right there on the command line.

This is great for a couple of reasons. You never have to guess what code is hidden inside that alias. The full text of the command will be right there on the command line and in your history, so you'll never be surprised. It also means you can go back and tweak the command a bit.

What I did differently

There is only one thing I didn't like about the solution at hackerific.net. Instead of cleanly defining your global aliases with the alias command you have to add your aliases into a hash table. His code uses that hash table to expand the aliases on the command line and also to create your actual global aliases (so that they still work at the end of the line).

I like that you only have to define them once but I wanted to build the hash table out of the global aliases that are already defined.

I managed to parse the output of alias -g and stuff it into the hash table, but I wasn't able to make it work without piping the output to Perl and sourcing the output back in. I tried to make it work with pure shell code, but none of the magic I came up with worked.

Here's the code!

typeset -A abbrevs

# Begin Ugly Hack

alias -g | perl -e "print 'abbrevs=('; while (<>) { s/^(.+?)='(.+)'/'\$1' '\$2' /g; s/'\\$/\\$'/g; print; } print ')';" > /tmp/cheater.zsh
source /tmp/cheater.zsh

# End Ugly Hack

globalias() {
   local MATCH
   LBUFFER=${LBUFFER%%(#m)[_a-zA-Z0-9\-]#}
   LBUFFER+=${abbrevs[$MATCH]:-$MATCH}
   zle self-insert
}

zle -N globalias

bindkey " " globalias
bindkey "^ " magic-space           # control-space to bypass completion
bindkey -M isearch " " magic-space # normal space during searches

You can probably just paste this into your .zshrc near the end, after all your global aliases are defined.

oh-my-zsh plugin

I'm running my copy as an oh-my-zsh plugin. I haven't uploaded it to github yet, though. I'd prefer to eliminate the ugly pipe-and-source lines first. I may have to upload it as is if I don't get around to improving it, though.

You can download my plugin here, it is identical to the code above, though.

I've tried my best to find native Linux games, and there are plenty of awesome independent games that run natively on Linux. The problem is that the vast majority of these games require some sort of analog input, usually a mouse. My cabinet has no analog controls...

I have been keeping my eye out looking for Windows games that run well under Wine. There are a large number of Indie games that run very poorly under Wine, most of them were created using GameMaker.

I saw the Buy Games Not Socks and I immediately hoped that Mactabilis would run under wine. I downloaded the demo and it ran absolutely flawlessly, so I immediately purchased the bundle.

It even runs well on my arcade cabinet with it's ancient Nvidia 6200LE video card, even with the video flipped upside down. I do have to run it with the resolution set to 960x540, though.

I was happy to learn that everything in the game can be controlled with the arrow keys and a handful of buttons. After mapping everything I would need I still had one button left over on my six (seven, counting start) button control panel.

Mactabilis is an awesome side scrolling shoot 'em up. The first thing I noticed when I started playing was that the game felt backwards! I'm so used to my ship being on the left.

This was very easy to get used to. For half of the first level your ship is moving from left to right, on the second half you reverse direction.

Mactabilis has an interesting feature that I've never seen in a shoot 'em up before. You can hit a button to move your ship between the foreground and the background layers. Enemies and obstacles seem to occupy one of the two layers.

If things get too crowded or dangerous in the current layer you can just hit a button to move your ship into the opposite layer. Enemies in the other layer become transparent, blurry, and desaturated.

This is pretty neat but I was constantly forgetting that this option exists...

Mactabilis also seems to have a staggeringly huge number of weapons to purchase for your ship. I haven't had time yet to get very far into the game, so I can't really comment too much on this. I can say that the weapon screen has a seven by seven grid of weapons you can purchase. I can hardly wait to try some of them!

This hasn't really been that big of an issue for me. The battery only lasts about two and a half hours anyway, and there is no trouble reading the current charge left in the battery. I was hoping I'd eventually luck out and a kernel upgrade would magically start seeing the discharge rate. I'm up to 3.0-rc3 and still no luck there.

I didn't have any reason to attempt to fix this problem until yesterday. I installed a copy of the latest and greatest development version of Powertop, version 1.98. The new version looks very promising. I was interested in trying the new calibration feature. It looks like it does things like cycle your LCD brightness, perform disk i/o, and stress the CPU a bit while monitor power usage. This doesn't seem to work so well if Powertop is unable to read the battery discharge rate.

My DV8T has a quad core i7 processor and the BIOS version was F.11. I bought two more DV8T laptops last summer, one for each of my parents. Theirs have Core 2 Duo processors. Luckily for me, I have a VPN between here and my parents' house. I was able to ssh into my mother's laptop and take a look around. She has BIOS version F.24 and ACPI has no trouble reading the discharge rate.

Updating the BIOS

I rarely update the BIOS on my machines. As far as I'm concerned, if it ain't broke don't fix it. I decided that, in this case, it seemed to be working on another very similar machine (with the same BIOS) that it was worth giving it a shot.

Here's the rub. HP's flash utility only runs on Windows. I don't have Windows installed anywhere here at home. I probably have an old Windows XP CD squirreled away somewhere, but I have no idea where it is. I'm disappointed that they don't have a DOS utility like most of their competition does. It isn't a deal breaker. I'd still buy another laptop like this, I don't often want to flash the BIOS on any of my laptops.

I tried a BartPE boot disk. It blue screened. I ended up downloading the Windows 7 Enterprise 30 day trial from MicroSoft and I installed it on an old spare laptop drive. This part of the journey is pretty uninteresting. Windows 7 installed just fine and the BIOS flashed with just a few clicks.

Total waste of time

I'm up to BIOS version F.25. Here is the result:

wonko@zaphod:~$ cat /proc/acpi/battery/BAT0/state
present:                 yes
capacity state:          ok
charging state:          discharging
present rate:            unknown
remaining capacity:      4640 mAh
present voltage:         16434 mV
wonko@zaphod:~$ cat /sys/class/power_supply/BAT0/current_now 
cat: /sys/class/power_supply/BAT0/current_now: No such device
wonko@zaphod:~$

Note the present rate: unknown and the No such device. I'm guessing this ACPI problem only exists on the Core i7 DV8T laptops. At least I got to see how much the Windows install process has (and hasn't!) changed between Windows XP and Windows 7, for whatever that is worth...

Ubuntu 11.10 now has apt-btrfs-snapshot available in the universe repository. This is an awesome little script that hooks into apt to create a snapshot right before packages are installed or upgraded.

The only thing I wasn't too happy about was that apt-btrfs-snapshot doesn't do any cleanup of old snapshots, so things were getting cluttered pretty quickly:

Cleaning things up a bit

I threw together my own little snapshot cleanup script to hook into apt. It automatically removes all but the five most recent snapshots. That should be enough history to keep me safe.

Still using btrfs-snap as a safety net

I'm still using [btrfs-snap](http://blog.patshead.com/2010/09/simple-automated-btrfs-snapshots-with-btrfs-snap.html) on my root volume but I'm not keeping anywhere near as much history as I used to. I'm only keeping a few hourly snapshots and one weekly snapshot. I'll probably end up dropping the weekly snapshot.

This is my apt-btrfs-snapshot-cleanup.sh script:

#! /bin/bash

DEVICE=/dev/sda2
KEEP=5
MP=`mktemp -d`

mount /dev/sda2 $MP

ls -dr $MP/@apt-snapshot-* | tail -n +$KEEP | while read snap ; do
  btrfs subvolume delete $snap
done

umount $MP

I also created a file called /etc/apt/apt.conf.d/81-btrfs-snapshot-cleanup containing this line:

DPkg::Pre-Invoke {"if [ -x /usr/bin/apt-btrfs-snapshot ] && apt-btrfs-snapshot supported; then /home/wonko/bin/sbin/apt-btrfs-snapshot-cleanup.sh; fi "; };

This will make apt run this script right after it takes a snapshot. Just tweak that line to match the location of your apt-btrfs-snapshot-cleanup.sh script.

I have probably been entertaining the idea of replacing top with htop for quite a few years now. I have even made the attempt a few times. Familiarity and muscle memory always brought me back to top. Until now.

Some advantages of htop

The biggest advantage of htop for me is that it combines the functionality of top and iotop into a single screen, since iotop lets you add disk i/o related columns to the output. This feature has saved me quite a bit of time and thought. I don't have to cross reference processes between top and iotop now, and I also don't have to fire up vmstat as often as I used to.

You can also highlight a process and hit l to get a list of open files for that process. I haven't needed to use lsof very often since I learned about this feature.

There are some other small advantages to htop. You can scroll the display horizontally with the mouse which is makes it easy to see the entire command line of a command. You can also select multiple processes to kill or renice.

htop also lets you configure the header area and which columns are displayed in a much more visual manner than top.

Some minor problems with htop

I'm not really a fan of htop's color schemes. It ships with a half dozen color schemes that are all either very colorful or completely monochromatic. The color schemes are hard coded so there is no easy way to define your own.

There are top compatibility keys for sorting by memory and cpu usage but there is no key to sort by i/o. To do that you have to hit F6 or > and use the arrow keys to select the i/o column. This is still better than reaching for iotop but it isn't exactly ideal. Setting CPU affinity has the same problem.