Here’s a step-by-step tutorial of creating a screencast, converting it into an .flv file, and uploading it to your site with an embedded Flash player. (more…)
Archive for the ‘utilities’ Category
Use Sphinx for documentation
Friday, April 25th, 2008I’ve been doing quite a bit of code documentation lately, and I decided to try and figure out the best tool to use. I found it. It’s called Sphinx, and you can see what the documentation looks like by checking out the documentation for Python itself (v. 2.6 and 3.0).
Here’s how to get started using Sphinx. (more…)
Persistent SSH sessions
Thursday, March 13th, 2008The screen program, among other useful things, lets you keep an SSH session running even after you disconnect from SSH. Here’s how to use it.
SSH in.
ssh user@hostname.comOnce on the remote machine, set up a named screen:
screen -S myscreenIn another terminal, open another SSH connnection and start another screen:
screen -S mysecondscreenYou can see they are there by using, in either of the terminals,
screen -lsThis does NOT start screen, just lists the different screens.
You can now disconnect the SSH connections. When you reconnect, you can use
screen -r myscreenor
screen -r mysecondscreento reconnect to the one you want.
Setting up and using an SVN repository
Thursday, March 13th, 2008Install subversion (Ubuntu)
sudo apt-get install subversionMake a directory to store the repositories
mkdir /path/to/repositoryCreate the repository
svnadmin create /path/to/repositoryImport existing files into repository
svn import /path/name/to/foo file:///path/to/repositorywhen you checkout this repository, it will create the directory foo. So to get the svn repository in my ~/work directory as ~/work/foo I would go to ~/work, then
svn co file:///path/to/repositorythat is, don’t make a new dir dir called foo and import into there . . . it will make its own dir.
Check out locally
svn checkout file:///path/to/repository /local/workdirCheck out remotely through an ssh connection
svn checkout svn+ssh://user@hostname/path/to/repository/on/remotehost /local/workdirUpdate local copy from SVN
svn updateCheck what’s been changed
svn statusResolve a conflict
svn resolved filenameSend these changes to SVN (editor will prompt for revision notes, must be non-empty)
svn commitSend these changes to SVN, and specify logfile to send as comments
svn commit -F logfileA more secure SSH configuration
Thursday, March 13th, 2008Some easy ways to configure SSH to be a little more secure:
Edit /etc/ssh/sshd_config as root.
- Change the port (default is 22)
- Change “PermitRootLogin yes” to “PermitRootLogin no”
- AddUser username
- save and quit
- restart the ssh server: sudo /etc/init.d/ssh restart
More info here:
http://ubuntu-tutorials.com/2007/02/14/what-you-ought-to-know-about-securing-ssh/
SSH: Add public key to remote server
Thursday, March 13th, 2008Easy way to add public key of this machine to a remote machine:
ssh-copy-id -i ~/.ssh/id_dsa.pub root@fileserver01More good info here:
http://ubuntu-tutorials.com/2007/02/05/unattended-ssh-login-public-key-ssh-authorization-ssh-automatic-login/
Remote MySQL using SSH
Thursday, March 13th, 2008Step 1: SSH forwarding
First, forward the local port 3307 to 3306. That is, when you access the local port 3307, it will redirect it to port 3306 on the remote host.
ssh -fNg4 -L 3307:127.0.0.1:3306 user@hostname-f sends SSH to the background
-g allows remote hosts to connect to local forwarded ports
-N don’t execute a remote command
-4 this was key! Forces IPv4. Kept getting “bind: Address already in use” errors because I didn’t have this.
-L the forwarding magic happens here . . . syntax is localport:localhost:remoteport
Step 2: Connect to mysql on port 3307
. . . which will redirect to port 3306 on remote host.
mysql -u root -h 127.0.0.1 -P 3307 -pand you’re in!
Converting between SVG, EPS, and PDF
Tuesday, February 12th, 2008Sometimes you want to be able to tweak a plot in R that was saved as a PDF or an EPS.
Use this to convert an eps into svg for editing in Inkscape:
pstoedit -f plot-svg input.eps output.svgThen save the SVG in Inkscape as a “Plain SVG”, and use
convert input.svg output.pdf
Split the pages out of a PDF, or merge PDFs into one
Sunday, January 27th, 2008Using the free open source program PDF Toolkit, you can operate on PDFs quite easily. (more…)
Convert images into a movie with mencoder
Saturday, January 26th, 2008Here’s how to create a movie out of a collection of images, along with a more detailed example on creating multiple images with nested folders of images. (more…)