Excel won't open files when I double-click them

My Excel, for some reason, decided that when I double-clicked a spreadsheet file, it would launch but wouldn't actually open the file. This has happened to me before, and I found a page somewhere on the net that told me how to fix it. I couldn't find that page, but I did figure out how to fix it, so I'm posting the solution here.

1. Go into Excel Options
2. Select Advanced
3. Scroll down to the General subheading
4. Uncheck the box next to Ignore other applications that use Dynamic Data Exchange (DDE)

Beyond Compare with Mercurial

To get the excellent Beyond Compare to work as my graphical diff tool in Mercurial (Hg) on Windows, I needed to add the following lines to my mercurial.ini:

[extdiff]
cmd.bcomp = C:\Program Files\Beyond Compare 3\BComp.exe
opts.bcomp = /ro /solo

Then, from the commandline, I can use

hg bcomp

to get a diff of all changes in the directory, or I can specify a filename to see differences in it. Without the /ro /solo, I ran into issues with the temporary directories in a dir diff being deleted immediately before Beyond Compare got a chance to compare them. That's because without them, Hg thinks that Beyond Compare completed immediately. Those options tell Beyond Compare to hold off on telling Hg it's done until after you have manually closed Beyond Compare.

Beaglebone Flash Image on Linux

The BeagleBoard website assumes you're using Windows in all of its instructions. I am running Linux Mint and wanted to update the OS image on my SD Card.

My ThinkPad has a built-in SD card reader. I didn't know what Linux called it, but I did see SD cards I put in show up in my file browser. Turns out you can list your disk drives with the command:

sudo fdisk -l

I got output like this:

Disk /dev/mmcblk0: 3904 MB, 3904897024 bytes
255 heads, 63 sectors/track, 474 cylinders, total 7626752 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

        Device Boot      Start         End      Blocks   Id  System
/dev/mmcblk0p1   *          63      144584       72261    c  W95 FAT32 (LBA)
/dev/mmcblk0p2          144585     7132859     3494137+  83  Linux

Then, I used this command to "burn" the image to the card:

sudo dd if=./Angstrom-Cloud9-IDE-GNOME-eglibc-ipk-v2012.12-beaglebone-2013.06.20.img of=/dev/mmcblk0

You might want to stick a "time" on the front of that command: it's going to take a while (a little more than half an hour for me). You can check on its progress by using ps -a to get the pid of dd, then send it a USR1 signal with sudo kill -USR1 pid. That will cause it to print status information to stdout.

How do I concatenate text files on Windows?

Strangely enough, I've had this same question asked of me twice within the last week, so I figured I'd post it here.

At the command prompt, use this command:
type *.txt > outfile

If you name outfile with the extension .txt, you'll actually wind up with stuff duplicated because the *.txt will cause the output file to be input, too!

What does dcommit stand for in git svn?

It took me some scrounging around to find it, and I don't remember where I did, but git svn dcommit means delta commit.

Git stores full versions of files (and relies on compression to make everything as a whole a manageable size), but SVN stores deltas, or differences between files.

So, when pushing your changes to an SVN repo, git has to build deltas out of all the commits you are sharing and then commit those to the SVN repo.

Building Mercurial (hg) -- fatal error: Python.h: No such file or directory

The version of Mercurial you get using sudo apt-get install mercurial is a relatively old one. But, if you download it from http://mercurial.selenic.com/, you can get the latest. However, in a fresh install of Linux Mint, I got the following error when I tried to run sudo make install:

mercurial/base85.c:13:20: fatal error: Python.h: No such file or directory
compilation terminated.

To fix this, you need to install the python-dev package using:

sudo apt-get install python-dev

You'll need to install python-docutils, too. Then you can run make install.

Installing python-markdown on Linux

I am running Lubuntu. I couldn't find these directions quickly using a google search, so maybe this will help someone else out in the future.

First, install python: sudo apt-get install python

Next, install "pip": sudo apt-get install python-pip

Now, for markdown: sudo pip install markdown

 To run it, use markdown_py input.md