Using an enum flags property to hold users’ roles is just one trick I’ve learned from @SeiginoRaikou, one of my co-geniuses at InterWorks.

Historically I have always modeled user roles with a Role table and a many-to-many relationship with my User table.

    +-------------------+
    | User              |
    |-------------------|
    | UserId   : int    +-------------+---------------+
    | UserName : varchar|             | UserRole      |
    +-------------------+             |---------------|
                                      + UserId : int  |
    +-------------------+             + RoleId : int  |
    | Role              |             |---------------+
    |-------------------|             |
    | RoleId   : int    +-------------+
    | RoleName : varchar|
    +-------------------+

Compared to a flags enum approach this is downright wasteful. With flags, there is only ever one column to work with and it is an integer. No second table. No joins or second query.

Have you ever wondered why some web pages have a great preview when linked on Twitter, Facebook, or Google+ while others look so lacking?

<img alt="Screenshot of Google+ link previews" src="g-vs.png" style="width: 450px" />

<img alt="Screenshot of Twitter link previews" src="tw-vs.png" style="width: 450px" />

What you are seeing are formats such as the Open Graph protocol and Twitter Cards at work.

There are a few folders that I spend a lot of time and it is surprisingly slow to type cd c:\path\to\my\project many times a day. I solved this by creating a module that allows me to bookmark directories and navigate to them using aliases. Simply put, I can shorten the previous command to g project.

Usage looks like this:

Set-Bookmark <name> <path>
Get-Bookmark # to list all
Get-Bookmark <name>
Remove-Bookmark <name>
Clear-Bookmarks
Invoke-Bookmark <name>

I alias Invoke-Bookmark as g for speed.

UNIX has the time command that will measure the execution time of a program. Timings are returned for the wall clock and CPU time. It looks something like this.

$ time ping google.com -c 1
PING google.com (74.125.225.232) 56(84) bytes of data.
64 bytes from dfw06s26-in-f8.1e100.net (74.125.225.232): icmp_req=1 ttl=54 time=19.7 ms

--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 19.767/19.767/19.767/0.000ms

real   0m0.173s
user   0m0.010s
sys    0m0.100s

The real, user, and sys information at the end is the output from time. StackOverflow has a great explanation of what those values mean.

MKLINK is a very useful utility on Windows. Unfortunately there aren’t any native PowerShell functions that replace it so we still have to shell out to the command prompt.

This can be made less painful with a helper function that will pipe all arguments to the MKLINK command.

function mklink { cmd /c mklink $args }

Personally though, I prefer to use native PowerShell functions whenever possible so I put together a module that provides wrappers for the key functionality of MKLINK.

Usually it is best to configure your terminal service policy to log out disconnected sessions, however there may be cases where you only want to kill specific applications when the user disconnects.

This is easy to do with a PowerShell script that you run periodically as a scheduled task. The processes won’t be killed immediately when the user disconnects but will be killed shortly after.

This script will, by default, only kill the OUTLOOK processes in disconnected sessions after waiting 15 seconds for it to gracefully close. It is trivial to tweak the script to kill whichever processes you care about.

We all know the news is biased. Media slants to the left or the right. Bias is natural and very difficult to avoid.

I don't read the news much but the recent public shootings in Aurora, Colorado and at the Sikh temple in Wisconsin have made my social media feeds flutter with the topic of gun control with points from all sides.

Today I listened to an episode of Common Sense with Dan Carlin, a podcast that I occasionally listen to and always enjoy. He does a good job, in my opinion, of thinking about situations from both sides of the fence.

TL;DR;

Update: If you want to save some time, skip reading this and just use my PowerShell Script Boilerplate. It includes an excellent batch file wrapper, argument escaping, and error code bubbling.

PowerShell.exe doesn’t return correct exit codes when using the -File option. Use -Command instead. (Vote for this issue on Microsoft Connect.)

This is a batch file wrapper for executing PowerShell scripts. It forwards arguments to PowerShell and correctly bubbles up the exit code (when it can).

Thanks to Evan Miller, adding VIM syntax highlighting for Nginx config files is a breeze.

First, install VIM if you haven’t already. On Arch Linux, it goes like this:

> pacman -Sy vim

Create a folder for your VIM syntax files.

> mkdir -p ~/.vim/syntax/

Download the syntax highlighting plugin.

> curl http://www.vim.org/scripts/download_script.php?src_id=14376 -o ~/.vim/syntax/nginx.vim

Add it to VIM’s file type definitions. Make sure to adjust the path to your Nginx installation if you need to.

Storing your Raspberry Pi’s configuration files in Git is a great way to protect yourself from really bad accidents. You get a backup of all your configs and revision control to rollback those nasty changes. Best of all, you don’t have to manually create backup copies of each individual file. (cp rc.conf rc.conf.bak anyone?)

I should note that I’m running Arch Linux ARM, but this should apply fairly equally to Debian and other distros.