On Wed, Dec 17, 2003 at 01:57:22PM +0100, David Fokkema wrote: > Hi group, > > I was not entirely sure what to put in the subject line... > > I did a very simple physics experiment involving two strings, two > weights and one pulley. I'll spare you the details, but by varying one > of the two masses, I measured the angle one of the strings made with the > vertical. I got these results: > > # m2 alpha > 0 0 > 10 12 > 20 23 > 30 32 > 15 18 > 25 27 > 12 14 > 22 24 > 27 29 > 17 20 > > where the first column is the mass of the second weight and alpha is the > angle, in which I made an error of ±1 degree. So far, so good. > > Now, I want to plot in gnuplot the following: m2 along the x-axis, but > the tangent of alpha with errorbars along the y-axis. So, I have to > process this data somewhat further to obtain a second data file with > three columns: m2, tan alpha-low, tan alpha-high. > > Of course, I could use gnumeric or something like that, but I'm > wondering if there are command-line tools out there that could do the > job. Or should I use a scripting language? perl? awk? bc? Efficiency is > not the problem here, ease of use is. >
The command-line tool to use is awk. e.g. awk ' {print $1, $2-D, $2+D;} ' infile >outfile where D is the deviation in alpha. D can be computed by a subroutine function, but I don't have enough info to write plausible example code. HTH -- Paul E Condon [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]