pink noise
Pink noise can be used to mask distracting sounds in the environment around you. It can be useful for providing a neutral sonic background for concentration.
The program speaker-test comes in the alsa-utils package, and provides pink noise by default. This is described by its man page as “perceptually uniform noise”. There are a number of other options, but for a quick noise generator, speaker-test is very handy.
What’s my ubuntu (or debian) version?
I have a number of machines running various OS releases. Sometimes I need to check what flavor or relase I’m running on the current machine.
While uname -a will show the Linux kernel version, there are a few ways to get more information.
Here are three possibilities:
cat /etc/issue
cat /etc/lsb-release
and my favorite:
lsb_release -a
Here’s some sample output from lsb_release:
$ lsb_release -a
LSB Version: core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch:core-4.0-ia32:core-4.0-noarch
Distributor ID: Ubuntu
Description: Ubuntu 10.04.1 LTS
Release: 10.04
Codename: lucid
The “lsb” in these commands refers to the Linux Standard Base. For more information, see the Linux Foundation .
lucidor
I’ve been looking at a number of different ebooks and e-readers lately. Lucidor is a project which is a little better looking than some of the older apps, but it is still pretty early in development.
Here’s a copy of lucidor 0.9, which was difficult to find due to problems with the lucidor site:
md5sum: 08faa6b60df2dae654e70431aa2e7626 lucidor_0.9-1_all.deb.gz
sha1sum: 0397853f5c4fe013fe36aed71ec0aa219f7f35f2 lucidor_0.9-1_all.deb.gz
installing ntop on Ubuntu : problem with rrd directories
The ubuntu install for ntop is broken without some additional steps.
‘Ubuntu Bloke’ had the easy fix :
"Create the directories that for some reason are not created by the installer
sudo mkdir /var/lib/ntop/rrd
sudo mkdir /var/lib/ntop/rrd/graphics
sudo mkdir /var/lib/ntop/rrd/flows
sudo mkdir /var/lib/ntop/rrd/interfaces
sudo mkdir /var/lib/ntop/rrd/interfaces/eth0
sudo mkdir /var/lib/ntop/rrd/interfaces/ppp0
sudo chmod -R 775 /var/lib/ntop"
Ubuntu 10.04, Lucid Lynx, Released
Lucid Lynx has arrived. The release day was yesterday, though I’ve been running several systems on 10.04 since the alpha stage. It’s well done. I don’t yet have a use for the social networking tools/toys (the gwibber app and indicator-me gnome package), but I’m not unhappy with them either. The server image has been robust so far, but I haven’t thrown too much at it. I’m thinking of putting the netbook edubuntu version (à la the system 76 starling edubook ) on my older laptop to see how that flies. Looks like fun.
Stanford folding@home and origami on Ubuntu
If you’d like an easy way to run folding to help the Folding@Home Stanford research project, even on a multicore system, ‘origami‘ may be a good soultion. I like it a lot.
It starts on boot-up automatically, can set folding to commence according to a schedule, allows project and stat checks from the command line, and even allows centrally administered group deployments (for example, to a lab full of machines). It does make laptops run pretty hot (as the CPU is engaged doing protein folding simulations), so I limit it to short bursts on laptops, but it can be a great tool to help in contributing to the folding project. You can also set origami to contribute to the TeamUbuntu folding project if you’re interested.
converting a pdf into html (one file to many method)
Here’s an Ubuntu (and other linux/Unix?) tip taken from ehow .
To convert a pdf into navigable html (with images intact), you can use pdftohtml:
E.g.,
pdftohtml -c originalfile.pdf newname_template.html
Converting a book-length pdf using this method gave me a directory full of files, with consecutively numbered html files representing the pages. Names were based on the ‘newname_template’ supplied, as were the png image files. Not the prettiest, but functional, and viewable on devices lacking native pdf-rendering capabilities.
How to keep apache from autostarting on system boot for Debian or Ubuntu
An easy way to remove apache2 (or another system service) from the start up scripts in Debian or Ubuntu is to use the update-rc.d mechanism.
For instance:
# update-rc.d -f apache2 remove
The “-f” is required if you have existing scripts in /etc/init.d/apache2. If you are planning on manually starting apache, the “-f” is [barring heroic/quixotic effort to create alternatives] a requirement.
Otherwise, in this situation, you will see:
update-rc.d: /etc/init.d/apache2 exists during rc.d purge (use -f to force)
A good write-up is here:
http://www.debuntu.org/how-to-manage-services-with-update-rc.d
Ubuntu 9.10 (Karmic) Beta
Instead of ‘ do-release-upgrade ‘ as I did with my upgrade to 9.04 , going to the Beta of 9.10 I used
update-manager -d
No major problems. I did have to manually remove a couple of ppa entries from my /etc/apt/sources.list. Also, I changed from the generic ‘main server’ to a much, much faster (at the time) server. The easiest way to do this is via gui, as far as I know. Ubuntu will check for the fastest responding site if you use ‘System’ -> ‘Administration’ -> ‘Software Sources’ and ‘Select Best Server’,’ or use ‘Settings’ under the update-manager interface (‘settings’ is on the lower left) to get to the same place. I shaved off several hours from my package download by switching to a server that had some combination of proximity, light load, and high bandwidth. This involved a generous amount of luck, and probably the uneven demand associated with a pre-release version of the OS.
