Difference between revisions of "Gnuplot"
From Noah.org
Jump to navigationJump to searchm |
m |
||
Line 36: | Line 36: | ||
plot "ntpdate.log" using 1:10 | plot "ntpdate.log" using 1:10 | ||
</pre> | </pre> | ||
+ | |||
+ | == other examples == | ||
For using with `cdck` | For using with `cdck` | ||
Line 46: | Line 48: | ||
set xlabel 'Sectors (2Kb/sec)' | set xlabel 'Sectors (2Kb/sec)' | ||
set ylabel 'Reading time (usec)' | set ylabel 'Reading time (usec)' | ||
− | set logscale y | + | #set logscale y |
plot 'cdck-plot.dat' with lines | plot 'cdck-plot.dat' with lines |
Revision as of 05:08, 29 November 2009
I use gnuplot from time to time. I don't know it well enough to do anything fancy, but I keep it in my toolbox.
Most of the time I just want to plot some points from a data file.
One of the first tricks I do is alias "gnuplot" to "gnuplot -persist":
alias gnuplot='gnuplot -persist'
This will tell gnuplot to keep an image displayed on the screen. By default gnuplot will close a display window as soon as it finishes drawing.
I don't run an ntp daemon.Instead, I just sync my clock once a day using ntpdate.
The ntpdate log file looks like this:
28 Jul 04:02:41 ntpdate[4781]: step time server 192.43.244.18 offset 13.828862 sec 29 Jul 04:02:45 ntpdate[19059]: step time server 192.43.244.18 offset 13.838561 sec 30 Jul 04:03:36 ntpdate[17510]: step time server 192.43.244.18 offset 13.844762 sec
I save the output from ntpdate to a log file. I can plot the daily clock drift using this gnuplot script:
set data style errorlines set title "Daily clock offset\nnegative means clock runs fast" set xlabel "Date" set xdata time set timefmt "%d %b %H:%M:%S" set format x "%d/%m" set ylabel "Required offset (negative minutes fast)" set yrange [ -1.0 : 30.0] set grid plot "ntpdate.log" using 1:10
other examples
For using with `cdck`
#!/usr/bin/env gnuplot set data style errorlines set terminal x11 set grid set xlabel 'Sectors (2Kb/sec)' set ylabel 'Reading time (usec)' #set logscale y plot 'cdck-plot.dat' with lines pause -1
old style, depricated:
set terminal png #gif small size 640,480 set title "Daily clock offset\nnegative means clock runs fast" set data style fsteps set xlabel "Date" set timefmt "%d/%m/%y\t%H%M" set yrange [ -4.6 : -4.8] set xdata time set xrange [ "25/06/00":"29/08/00" ] set ylabel "Required offset (negative minutes fast)" set format x "%d/%m" #\n%H:%M" set grid set key left plot "data.dat" using 1:10 reset