Kurt's Weblog

I got to spend yesterday at Scripps Institution of Oceanography. However, my list of people that I wanted to track down and talk to is longer than the list of people that I did manage to talk to. I taught a lecture for David Sandwell and Helen Frickers' SATELLITE REMOTE SENSING âÄì SIO 135/SIO 236. I always worry that my lecture style is jarringly different than what the students are used to, but the students a lot of really great questions, which is totally awesome!

After teaching, I got to sit down with Lisa Tauxe and Neal Driscoll and talk shop. Turns out that Lisa and Peter Shearer have turned the notes from their into a book for (via LaTeX!): Introduction to Computing at SIO: Notes for Fall class, 2011 (SIO 233). The 235 page document covers the UNIX Command Line (using csh, NOT bash ), Fortran, GMT/Fink, Python, NumPy, Matplotlib, Scipy, and LaTeX. It's great to see other takes on teaching this kind of thing. The differences between teach styles and content are what make the ecosystem of courses on the web useful and interesting. I would not cover Fortran and would swap csh/tcsh for the much more power pair of bash/ipython, but you should pick and choose the parts that you want for all that's out there. This book gets to material that I wanted to teach last fall but never got to write up.

Scientists hope OSU whale-tracking data can reduce accidental deaths

A multi-agency team of scientists has launched a project to
reduce the number of whales killed from ship strikes and entanglement
in fishing nets by identifying high-risk areas along the West Coast of
the United States. ...

Check the press release for more. Bruce Mate at OSU.

Is this connected to the WhaleAlert folks in New England in any way?

I have been pushing hard to get my workflow straight (it's shifted a fair bit this year). Back in 2004, I met Aurelio on the JPL MER mission. He was seriously rocking the gnu screen. I got to hang with Aurelio last week when Code for America, where he currently works, hosted the geomeetup about RedHat's OpenShift. I asked Aurelio if he would share some of his wizardry with screen. I am just getting into using "emacsclient -nw" to connect to an existing emacs session from an ssh'ed shell session, but the emacs shell never quite does it for me. So here is what Aurelio had to say:

Guest post by Aurelio

I normally use screen as soon as I log on to a remote server for the first time, essentially as a means to make sure that the session stays alive in case the connection is dropped.

$ ssh aurelio@tinio.org
$ screen

This means that I can just log back in to the server and continue working from where I left off.

$ screen -r

I've found this to be really useful for a few scenarios logging, db, irc, and at time's as a poor man's daemon. For logging, it's nice when I do something like apt-get upgrade on a lot of packages and have the peace of mind that if my laptop battery dies out the process continues on the server. For IRC, I continually have irssi running so that I can look back at conversations that I missed. As a poor man's daemon, I sometimes run a `./manage.py runserver` for development testing.

There are other scenarios as well, and it essentially let's me tab through windows on a remote terminal w/o having to log in for each session.

create new window: ctrl-a c 
switch to previous window: ctrl-a p
switch to next window: ctrl-a n

The session windows can also be named with:

ctrl-a A

I usually have them named, logging, runserver, working, etc.. which can be viewed with:

ctrl-a "

Finally, to detach the session and go back to the regular terminal:

ctrl-a d

However, with all that said my use of screen has actually diminished quite a bit since the JPL days and with the advent of services such as heroku where there is no server to 'ssh' into. I've mainly only been using it for IRC, but even that might be going away soon with the use of something like irccloud.com which I have started to really like.

Update 2012-Jun-19: Mark Sibenac suggested Byobu to go along with GNU screen or tmux.

Today, I finally got myself a copy of VMWare Fusion 4 for my MacBook Air with 10.7. I definitely works much better than VMWare Fusion 3 did on 10.6 or 10.7 and I'm saying that only after having created my first virtual machine with it. I only logged in far enough to open a terminal, run uname and cat /etc/lsb-release.



Made it a bit farther now that the ubuntu update servers seem to be happy again.

virtual-machine-ubuntu-12.04.org

27 lectures recorded last fall as audio. I've converted 7 to youtube videos. Only 20 more to go.

I am not directly in the middle of things with the AIS whale notice app these days or I would have thought to do this before the outage, but CCOM did some network maintanence this evening and was off the network for a couple of hours. That means that no matter what access method you use (AIS+wifi, 3G+internet, wifi+internet, or wifi+satellite+internet), you would not have been able to have seen the buoy updates. The green buoys (or gray) will dissapear in 15-20 minutes and any existing yellow bouys with whale detections that your iPhone or iPad have already received should stay on the phone for up to 24 hours. I haven't looked to see what today's activity has been, but the app is currently showing all buoys as grean (no whale detected in the last 1-20 minutes).

It's slow going putting my audio and video recordings together into videos, but I am getting there. It helps that I am starting to get desensitized to hearing my own voice. Last fall, that drove me nuts while doing the first past edits of the audio recorded with a Sansa Clip that I wore. That got rid of the bazillion um's, ah's and false starts that I do way to frequently. Recordings typically went from over 1.5 hours to under an hour.

Here are the MP4 lecture videos that I'm uploading to YouTube. CC license so feel free to pass them around or even edit them.

Lecture 11 talks about using the ipython shell and basic python data types.



Lecture 12 covers ipython log files, reading comma separated values (csv) data, and using emacsclient to allow ipython to request emacs to edit a file.



Lecture 13 starts off with using ntpdate to set the clock. I then attempted to show traceroute, but then remembered CCOM's network totally blocks that. I start into python talking about true/false boolean logic in python. I then show running python scripts from inside an ipython shell with the "run" command and demonstrate a simple function and a class.



I haven't been brave enough to look at the YouTube automatic speech-to-text to see if it is doing any better than last fall. YouTube definitely does not understand Python and Emacs speak.

And a random after throught... I was reading for 2 minutes about rope and ropemacs. Rope lets emacs and python interact. If only I had infinite time! Ben Smith (the CCOM/Captain Ben version of Ben Smith, not Google's Ben Smith) pointed me to these last fall and I never got around to looking at them. And to take this to an extreme tangent: For all those out there who are getting fired up about crowd source / DIY bathymetry and hydrography, check out Ben's Hydrography page where he describes his survey setup that he put together a few years back.

I meant to blog this a while back when I first got a copy of William's thesis.

William Eucker, "A Geospatial Analysis of Arctic Marine Traffic", PhD dissertation, University of Cambridge, 2011, 156 page.

Recent changes in Arctic Ocean climate dynamics and marine
activity in the region require re-evaluation of physical operating
conditions, ship traffic patterns, and policy requirements. This study
used (1) government surveys, (2) vessel reports, and (3) Automatic
Identification System (AIS) messages to characterize the spatial and
temporal variability of surface vessel traffic in relation to various
sea-ice conditions on the Arctic Ocean during a year-long study from 1
April 2010 to 31 March 2011. Data sources, methods of analysis, and
errors were discussed. Three principal topics were examined.

First, sea-ice cover on the Arctic Ocean was analysed to determine the
physical access for marine operations. Daily sea-ice concentration
data based on satellite passive microwave measurements were used to
calculate the extent of open water and duration of the sea-ice
season.

Second, ship traffic on the Arctic Ocean was analysed to determine the
present patterns of human activity. Time-stamped AIS messages encoded
with Global Navigation Satellite System (GNSS) positions received by a
commercial satellite constellation from north of the Arctic Circle (66
Second, ship traffic on the Arctic Ocean was analysed to determine the
present patterns of human activity. Time-stamped AIS messages encoded
with Global Navigation Satellite System (GNSS) positions received by a
commercial satellite constellation from north of the Arctic Circle ( )
were used to calculate the distribution of vessels per unit
area. Satellite AIS data from SpaceQuest, Limited, were compared with
land-based vessel observations during the study period from the Marine
Exchange of Alaska and the Port of Longyearbyen.
Third, the spatial and temporal relationship between sea ice and
surface vessels on the Arctic Ocean was analysed to determine
potential policy implications. Three groups of marine operations with
distinct characteristics were determined from the analysis: operations
in perennial open water, operations in the seasonal ice zone, and
operations in the perennial ice zone. Throughout the study year, most
ships north of 66 56N  operated in perennially ice- free areas, but
year-round operations also occurred in ice-covered areas.
The results from this study identify new pathways of information to
enable consistent pan-Arctic assessment of physical operating
conditions and ship traffic patterns. This approach provides novel
considerations to sustainably develop a safe, secure, and
environmentally protected Arctic Ocean.

He doesn't spend very much time on the issues that come up with AIS, but he does allude to some of them.

Despite the seeming availability of AIS as a new pathway of
information to contribute to scientific understanding of the
transforming Arctic Ocean, there are several factors that may
constrain its development and implementation. First, there are
legitimate privacy concerns about the ability to passively receive,
record, and disseminate information about a vessel. Surveillance is a
powerful method of regulating behaviour, especially in remote areas,
but ethical considerations should be further examined. Second, many of
these architectures are considered essential to national security, and
as a result, safeguarded. For example, the AIS satellites, AISSAT-1
and AISSAT-2, launched by the Norwegian government are managed by
their military. Third, the influence of environmental factors on the
satellite reception of AIS messages is a lingering question. For
example, atmospheric water vapour content is seasonally variable and
may increase with increasing open water. Fourth, there are competing
networks of ground stations, different satellite systems, and
deconfliction software. A thoughtful investment assessment would
require field tests and reliability studies further to this
analysis.

That only raises issues without giving any resources or hints to what the actually issues are. I've written lots about this and there will be more discussions to come.

Alex got me pointed at Amazon's Route 53 DNS. It took me about 10 minutes to setup an Amazon Web Services acount, activate Route 53 DNS, add 2 A records for schwehr.org and www.schwehr.org (why does everyone still assume the www???!!??), and point my registrar at the Amazon DNS servers. Hopefully I'll still be happy when the first bill comes. I certainly happy to have schwehr.org back up on the web. What will life without explicitely running bind look like? Certainly, the web interface was a lot simpler than working with bind config files.

dig schwehr.org

; <<>> DiG 9.7.0-P1 <<>> schwehr.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25228
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;schwehr.org.                   IN      A

;; ANSWER SECTION:
schwehr.org.            86400   IN      A       208.64.186.50

;; Query time: 69 msec
;; SERVER: 172.16.255.1#53(172.16.255.1)
;; WHEN: Tue May 15 09:47:20 2012
;; MSG SIZE  rcvd: 45

schwehr.org is currently in a "transitional stage"... it will be back soon. Too much going on with the group of use all hosting together for us to get this settled right away.

same post of blogspot

Jonny B asked a question this morning about tides and mbsystem. I didn't know the answer, but here is how I went about investigating. This is on a mac with 10.7 and fink. Hopefully this will give people some ideas about how to dig through what is around. "dpkg -L" lists the files in a package. As Jonny B said with a reference to the movie The Matrix, "Yowza, nice kung fu!". I didn't have a fish to give, so the best I could do was point to the tackle store and say you might be able to get what you need to fish in there.

# Which fink packages deal with sonar?
fink apropos sonar
# If you already know about mbsystem...
fink list mbsystem
fink install mbsystem
dpkg -L mbsystem | grep tide
# Nothing
cd ~/Desktop
ls /sw/src/mbsystem*
# See that the latest tar is version 5.3.1917
tar xf /sw/src/mbsystem-5.3.1917.tar.gz
cd mbsystem-5.3.1917
find . | grep -i tide
# Nothing

find . | xargs grep -l tide | wc -l
# 84
find . | xargs grep -l tide
# ./html/mbdatalist.html
# ./html/mbio.html
# ./html/mbnavadjust.html
# ./html/mbotps.html
# ./html/mbprocess.html
# ./html/mbset.html
# ./html/mbsystem.html
# ./html/mbsystem_how_to_get.html
# ./install_makefiles
# ./man/man1/mbdatalist.1
# ./man/man1/mbnavadjust.1
# ./man/man1/mbotps.1
# ./man/man1/mbprocess.1
# ./man/man1/mbset.1
# ./man/man1/mbsystem.1
# ...
# ./src/utilities/mb7kpreprocess.c
# ./src/utilities/mbcopy.c
# ./src/utilities/mbinfo.c
# ./src/utilities/mbprocess.c
# ./src/utilities/mbset.c

man mbset
# "Apply tides to bathymetry."

For some reason, Google's search engines seem unable to find this NOAA page. Perhaps a robots.txt setting? I'm link to these for myself.

Datum Transformation Grid (.GTX) Overview





See also:

NOAA's Vertical Datum tutorial
Vertical Datums: An Introductin and Software Review [OSGeo PDF]

I joined in to check out this live and found there was still a slot open, so I'm in the video. Check out Google Cloud Storage...

A quick look at QGIS, bash shell variables and for loops, using ImageMagick to make an animated gif of images from the Healy, and a first look at IPython.

Just a reminder to the community that the SAIC Generic Sensor Format (GSF) is not open source licensed code. You might be able to download the source, but nowhere does it give you any permission to use this code.

mkdir gsf
cd gsf
wget http://www.saic.com/maritime/gsf/download/gsf_0303.zip
unzip gsf_0303.zip
egrep -i 'copyright|license|gpl|apache|unclassified' *
gsf.c: * Classification : Unclassified
gsf.c: * Copyright (C) Science Applications International Corp.
gsf.h: * Classification : Unclassified
gsf.h: * Copyright (C) Science Applications International Corp.
gsf_dec.c: * Classification : Unclassified
gsf_dec.c: * Copyright (C) Science Applications International Corp.
gsf_dec.h: * Classification : Unclassified
gsf_dec.h: * Copyright (C) Science Applications International Corp.
gsf_enc.c: * Classification : Unclassified
gsf_enc.c: * Copyright (C) Science Applications International Corp.
gsf_enc.h: * Classification : Unclassified
gsf_enc.h: * Copyright (C) Science Applications International Corp.
gsf_ft.h: * Classification : Unclassified
gsf_ft.h: * Copyright (C) Science Applications International Corp.
gsf_indx.c: * Classification : Unclassified
gsf_indx.c: * Copyright (C) ACME Software, A Subsidiary of Fly By Night Industries, Inc.
gsf_indx.c:*   Classification:     Unclassified                                           *
gsf_indx.h: * Classification : Unclassified
gsf_indx.h: * Copyright (C) Science Applications International Corp.
gsf_info.c: * Classification : Unclassified
gsf_info.c: * Copyright (C) Science Applications International Corp.

That pdf that matches has no copyright or license information. While the web page implies that it is okay to use the code, in my feeble understanding of copyright law (I AM NOT A LAWYER), I see nothing that actually gives anyone rights to use the code. I wish SAIC would just pick something like the Apache, BSD or MIT licenses to make sure GSF gets as much use as possible. I first brought this issue up at the GSF workshop at Shallow Survey in 2008.

This time I tried laying the slides out that came from screen grabs using iMovie 11. Ouch. I will not want to do that again. It took a very long time to do and I don't think the results are really better. In this lecture, we go through using unix commands from the bash shell to build a Google Earth KML visualization of a ship working on the natural gas pipeline off the coast of Boston MA.

International Polar Year 2012 Conference from Knowledge to Action by Steve Maclean, President, Canadian Space Agency

We're now doing that in a number of ways: some tried and true,
some new and innovative, some experimental, and others still on the
drawing board.  One example with a distinctly northern focus is the
Maritime Monitoring and Messaging Micro-Satellite, or M3MSat, a
project in partnership with the Department of National Defence.
M3MSat, which includes an Automatic Identification System payload, or
AIS, will provide a test bed and demonstration platform that will
allow, government departments to track ocean going vessels on a global
scale.  The M3MSat AIS payload will be a complement to the CSA's
RADARSAT Constellation and DND's Polar Epsilon missions.  The AIS
system was originally designed as a collision avoidance system.  Ships
of a certain size were required to use AIS transponders to broadcast
their identity, location and heading.  But there limitations wereonly
ships and land-based receivers within a 50 nautical mile range were
capable of receiving that information.  However, by collecting those
AIS signals from space, we dramatically increase our ability to gather
and disseminate such information.  For government departments such as
National Defence, this new technology provides an unprecedented global
view of the world's shipping traffic.  Other departments also benefit.
For example, the information received from our microsatellites will
help Canada's Coast Guard identify and monitor maritime traffic
approaching or operating in Canadian waters.

This is pretty awesome what I was able to do using GDAL with VRT virtual files. I did a GDAL info and figured that the BAG is actually in EPSG2960 (not 100% sure of that). The results look very promising in QGIS.

gdalwarp -tr 2 -2 -te 369179 4773093 372861 4775259 -of VRT -t_srs EPSG:2960 \
     MENHMAgome01_8301/mllw.gtx  mllw-2960-crop-resample.vrt
gdal_translate mllw-2960-crop-resample.{vrt,tif}

Now, how can I do this just from python without using a system call to a command line?

How to do this? on Stack Overflow

Here is my take on how to do a color prompt. This particular version will be kind of slow if your python interpreter takes a long time to get started. But more interestingly, it shows how to do some interesting things in python.

First, to setup the environment. In fink:

fink selfupdate
fink install termcolor-py27
fink install git-py27
fink install python
fink install ipython-py27

On ubuntu:

sudo apt-get install python-git
sudo apt-get install python-stdeb # turn python packages into debs
wget http://pypi.python.org/packages/source/t/termcolor/termcolor-1.1.0.tar.gz#md5=043e89644f8909d462fbbfa511c768df
tar xf termcolor-1.1.0.tar.gz
cd termcolor-1.1.0
python setup.py --command-packages=stdeb.command bdist_deb
sudo dpkg -i deb_dist/python-termcolor_1.1.0-1_all.deb

Which git branch?

Now we can start constructing our prompt code in python. First lets try out the git handling module GitPython. We will first try it out in ipython.

cd ~/Desktop
ipython
mkdir foo
cd foo # definitely not
import git
repo = git.Repo('.')

This new "foo" directory is not under git control. As a result the git Repo call will fail like this:

InvalidGitRepositoryError: /home/schwehr/Desktop

This means we know that we have to trap an exception for when we open a directory that is not under git control. Let's try the case where a directory is under git version control.

!git init  # Tell git to start controlling this directory
# Initialized empty Git repository in /home/schwehr/Desktop/foo/.git/
repo = git.Repo('.')
# It should return nothing for you.
print repo.active_branch
# master

We are in the default "master" branch. You can do all sorts of fancy stuff with the git module in python, but for now, all we want is to be able to see which branch we are in.

Which directory are we in?

Getting the directory that we are in is pretty easy with os.getcwd, but we would like to have "~" in place of the home directory. I did this by using a regular expression substitution that is more powerful than just string replace.

import os
import re # get the regular expression module
homedir = os.path.expanduser('~') # What does the home directory path look like?
path = re.sub('^' + homedir, '~', os.getcwd()) # If the path starts with the homedir, use ~ 
print path
# ~/Desktop/foo

When did this happen?

Next we would like to have the current time in the prompt so that when we scroll back or come back to the computer later, we can remember when we were working in this shell. Helpful if you come back to a terminal a couple days later. While I know I'm always saying to use UTC time, it's probably best here to use local time to reduce confusion. You should always log UTC.

import datetime
datetime.datetime.now().strftime('%a %H:%M:%S')
# 'Mon 17:23:32'

Who am I

When you start really pushing your skills with the terminal and shell, you might sometimes find yourself logged in as different users on various computers. Not knowing who and where the shell is, can cause big problems. os.getlogin says who and os.uname says which computer. uname might not totally work on Windows/cygwin. In that case you will probably want to use the hostname info from the socket module.

os.uname()
# ('Linux', 'schwehr.org', '0.99', '#2 SMP Mon Apr 16 03:28:45 PDT 2012', 'x86_64')
os.uname()[1]
# 'server42.schwehr.org'
os.uname()[1].split('.')[0]
# 'server42'  # We now have the host name
'%s@%s' % (os.getlogin(), os.uname()[1].split('.')[0])
# schwehr@server42
who = _ # ipython command to stash the last

Put it all together

We now want to assemble our humble little prompt string. If we had saved each of the above, here is how we might put it together:

'  ({path})  {when}  [{branch}]  {who} '.format(**locals())
# '  (~/Desktop/foo)  Mon 17:33:00  [master]  (schwehr@schwehr) '

Color

But what if I want the color to be different for if we are in a git directory or if it is uncontrolled (or only by some other system like cvs, svn, hg, etc).

import termcolor
if branch:
  fg = 'white'
  bg = 'on_green'
else:
  fg = 'white'
  bg = 'on_blue'
prompt_clr = termcolor.colored(prompt, fg, bg, attrs=['bold'])
print prompt_clr

That's great, but the prompt does not go across the whole terminal window. We need to find out how wide the terminal is and pad the string. The unix tput command can tell us. It's worth wrapping this into a little function:

def get_width():
  proc = subprocess.Popen(['tput', 'cols'] , stdout=subprocess.PIPE)
  width = proc.communicate()[0].strip()
  return int(width)

Now we can just ask for the width and pad by the missing space:

prompt = prompt + ' ' * (get_width() - len(prompt)

Then we just have to print out the prompt and add a command prompt of a '#'. Why do I like the '#'? The hash / pound character is a comment, so if we accidentally paste lines from the terminal, there is less chance that something nasty (e.g. '; rm -rf *' or the like) doesn't get executed.

All in one file

Now assemble your ~/bin/prompt.py script:

#!/usr/bin/env python

__author__ = 'Kurt Schwehr'

import datetime, os, re, subprocess, sys

import git
import termcolor

def get_width():
  proc = subprocess.Popen(['tput', 'cols'] , stdout=subprocess.PIPE)
  width = proc.communicate()[0].strip()
  return int(width)

try:
  repo = git.Repo('.')
  branch = '%s' % repo.active_branch
except git.InvalidGitRepositoryError:
  branch = ''

homedir = os.path.expanduser('~')
path = re.sub('^'+homedir, '~', os.getcwd())

when = datetime.datetime.now().strftime('%a %H:%M:%S')

who = '%s@%s' % (os.getlogin(), os.uname()[1].split('.')[0])

prompt = '  ({path})  {when}  [{branch}]  {who} '.format(**locals())

prompt += ' ' * (get_width() - len(prompt))

if branch:
  fg = 'white'
  bg = 'on_green'
else:
  fg = 'white'
  bg = 'on_blue'

prompt_clr = termcolor.colored(prompt, fg, bg, attrs=['bold'])

print prompt_clr
print '# ',

How does this get called?

If run the script, it will look like this:



We need a program that will call this. There is a special bash variable call PROMPT_COMMAND that, if set, will be called each time that bash needs to present a prompt. We can create a bash function that will be assigned to PROMPT_COMMAND and will execute our prompt python command.

function prompt_command {
  PS1=$(~/bin/prompt.py)
}

PROMPT_COMMAND=prompt_command

You will want to put that in your ~/.bashrc

What does it look like?



I'm sure you can come up with all sorts of ways to improve on this. You might let it handle svn, hg, cvs, and other version control systems. It could tell you if there are files that have been modified but not committed. You could add in more of the features from the git __git_ps1 function that knows if you are merging, cherry picking and many other tasks.

echo $(__git_ps1)
(master)

It's up to you how far you want to take it.

See also:

http://www.gilesorr.com/bashprompt/prompts/
http://www.physics.ohio-state.edu/~ntg/780/handouts/Bash-Prompt-HOWTO.pdf

Thanks to Xah for getting more to write this all out.

Turning the way back machine to last fall. Here is the first lecture where I grab screen shots during lecture. I combined this with the audio that I edited with audacity and posted last fall. A bit hard to follow with only 54 still frames, but hopefully you appreciate some of the dialog between me and the students in the class. I especially like when people laugh at my lame jokes (when they realizing that I'm attempting one).

In this video, I have the class run Tetris inside of emacs. That is not a typo. Emacs most certainly includes Tetris.



I have been trying to figure out how best to make these videos. iMovie and KeyNote are definitely awkward for these kinds of things. I'm trying to get better at this. This first one was done by going through the slides in KeyNote with the audio playing. There is no going back for mistakes unless I want to start over for the whole thing.

discusson.apple.com
http://macmost.com/creating-videos-with-keynote.html
Hints Forum on MacWorld

And how would I do this on linux?

These two video (15 minutes each) are well worth watching to find out about the cruise that Monica is currently out on. They are drilling in almost 7000 meters of water before they even hit the sea floor!

Japan Trench Fast Drilling Project home page

Part 1:



Part 2:

Roland has been getting me to push my git skills. I wanted to merge one of his changes to libais for include guards in the C++ headers, but I didn't want to merge some of his prior changes. Git let's you do this with a "cherry-pick". I should have done this on a branch rather than master, but it's a start.

git checkout master
git fetch git://github.com/rolker/libais.git
git cherry-pick  45bcad5630052030d65e89e01605614da1d65ebc
# edit ais.h - fix that it pulled 1 line of a different change
git add ais.h
git status
git commit -m "use Roland's include guards"
git push

I am a little bummed that the changes are not shown with a link between our two master lines on the github network display.

libais schwehr network graph

See also:

Git Cherry Picking: Move small code patches across branches

I also used a stash to take some changes from master that I hadn't committed to a branch. Pretty awesome! How do you discard unstaged changes in git? [stackoverflow]

git stash save
git status
git branch -a
git checkout -b somebranch
git stash list
git stash show
git stash pop
git diff # Now your changes are in somebranch!
git commit -a -m "my comment about the change" # Don't forget to commit the changes