Curve fitting in R

This is a simple example of a linear fit where a perfect fit is distorted with the help of a gaussian function. This data is then fit to a linear model. The most important factor determining the success of a fit is the model equation and the second most important factor is suitable starting values of the fit variables (a and b in this case). Further, if you assign the output to a variable called fit, values a and b can be extracted using:

fit < - nls
coef(fit)[1]
coef(fit)[2]

Saving data frames in R

If 'df' is your data frame,
save(df,file="yourfile.rdf",ascii=TRUE)
save the data frame in to a .rdf file which is readable. Although the file as lot more data than you might want, loading the file back into R irons out any wrinkles.
load("yourfile.rdf")
http://stackoverflow.com/questions/8345759/how-to-save-a-data-frame-in-r

Edit Jan 2014
If however you really want to avoid additional lines in the saved file, try the following:
write.table(df,filename,row.names=FALSE,col.names=FALSE)
This should produce a clean file with your data in a neat column.

Speaker and Mic settings on Ubuntu Linux

Although Skype and Google video get installed fairly easily on Ubuntu, bad sound settings could be a show stopper. Alsamixer controls the sound and mic and can be force rebooted using:

alsa force-reload
or
alsa reload

This usually fixes most problems. Other useful links:
http://askubuntu.com/questions/164518/hard-resetting-alsa-configuration
http://chriscarey.com/wordpress/2008/07/01/reset-alsa-sound-on-linux/
http://ubuntuforums.org/showthread.php?t=1068612
http://forums.bodhilinux.com/index.php?/topic/3800-solved-how-does-a-user-restart-alsa-without-rebooting/